Most people aren't confused, because they're not trying to be clear and rational.  They are definitely confusing to people who prefer specificity and operationally useful descriptions of experiences.

It is used to mean a very wide range of positive feelings, and should generally be taken as poetry rather than communication.  Another framing is that the ambiguity makes it very useful for signaling affection and value, without being particularly binding in specific promises.

Which is NOT to say it isn't "real".  Affection, caring, enjoyment, and willingness-to-sacrifice-for someone are all things that many individuals experience for other individuals.  The exact thresholds and mix of qualia that gets described as "love" varies widely, but the underlying feelings seem near-universal.

You are right, most people are confused.

I've spent quite a lot of time on relationship theory. It seems pretty clear that "love" means very different things in different contexts, and that different people interpret it differently. It also seems clear that this causes a lot of problems for people. I'd say that means they are confused. I am neurotypical, to at least a first approximation, and I'm pretty sure that most neurotypical people would benefit by understanding their emotions a good bit better than they do on average.

Yes, context does a lot of work. But when you're trying to talk or think about your relationships, it's useful to understand and communicate what type of love you're talking about with more accuracy than intuition usually provides.

Your breakdown of types of love is a pretty good start. The Greeks had at least their four words for love, but the important subtypes seem more numerous and nuanced than four words account for.

This is also the case with other emotions; it's hard to understand them, there's a lot of variety and nuance, but understanding them is pretty worthwhile.

I can't comment on whether people are confused about what "love" means as I'm not sufficiently deep in love discourse to say. But one thing I'm noticing about your characterizations of love is that they are missing an indexical element to the point of approaching sollipsism.

Romance and sexuality makes for a good example. Consider the following scenarios:

• A woman is on a date with a man, which she enjoys until she sees that his home is a dump.
• A teenager has a crush on a celebrity, with elaborate daydreams about how cool the celebrity is, not realizing how much of this is a facade created for entertainment.
• A man visits a prostitute and feels excited as he causes her to orgasm, not realizing that she fakes it for the business.

In all of these cases, one could say that there is a disconnect between what people think about their object of attraction, versus what that object of attraction really is like.

A Bayesian of parsing this is that their feelings of attraction represents an estimate of how well they fit together, but that this estimate differs from how well they really fit together. The actual fit seems important to think and talk about, and one should probably coin a short word for it - or at least for the coincidence between actual and estimated fit. This could be called "true love".

“Love” is just a broad category of feelings. In English, if you need to be specific, there are specifiers, but most of the time context is enough. For instance, if I say, “I love my nephew,” you’re probably not thinking that I have romantic feelings towards him, but you might think that his presence makes me happy or that I’d be willing to sacrifice more for his benefit than typical for humans in general.

Are you going to have a perfect model of my feelings? No. You can never be specific enough for that. But you’ll likely be 9/10 right. Usually, that’s good enough.

I agree that:

• People commonly talk about love as black-and-white when it isn't.
• It is used as a semantic stopsign or applause light.
• Love is a cluster concept made up of many aspects, but the way people talk about love obscures this. The concept of "true love" serves to keep people in the dark by suggesting that the apparent grab-bag nature of love is just the way people talk, & there's an underlying truth to be discovered. Because experiences of love are fairly rare, people can only accumulate personal evidence about this slowly, so it remains plausible that what they've experienced is "just infatuation" or something else, and the "true love" remains to be discovered. People will fight about what love is in sideways ways, EG "you don't know what love is" can be used to undercut the other person's authority on love (when a more accurate representation of the situation might be "I didn't enjoy participating in the social dynamic you're presently calling love"). Different people will sometimes express different detailed views about what love is, but there seems to be little drive to reach an agreement about this, at least between people who aren't romantic partners. 

I once had the experience of a roommate asking if I believe in love. I said yes, absolutely, explaining that it is a real human emotion (I said something about chemicals in the brain). He responded: it sounds like you don't believe in love!

(I think this has to do with ambiguity about believe-in as much as about love, to be fair.)

So, a question: is 'love' worth saving as a concept? The way some people use the word might be pretty terrible, but, should we try to rescue it? Is there a good way to use it which recovers many aspects of the common use, while restoring coherence?

I do personally feel that there is some emotional core to love, so I'm sympathetic to the "it's a specific emotion" definition. This accounts with people not being able to give a specific definition. Emotions are feelings, so they're tough to define. They just feel a specific way. You can try to give cognitive-behavioral definitions, and that's pretty useful; but, for example, you could show behavioral signs of being afraid without actually experiencing fear.

I'm also sympathetic to the view that "love" is a kind of ritual, with saying "I love you" being the centerpiece of the ritual, and a cluster of loving behaviors being the rest of it. "I love you" can then be interpreted as a desire or intention or commitment to participate in the rest of it. 

If you are worried that nobody obsessively overanalyzes the concept of love in a desperate search for something solid at the base of the concept, worry no longer.

You seem to have arrived at the classical concept of "the four loves", referring to the four Greek words commonly translated as "love" in English:

• στοργή :: natural, familial affinity
• φιλία :: interest/enjoyment as coming from a free & rational agent
• ἔρως :: craving for unity with what is "beloved"
• ἀγάπη :: "to will the good of the other"

Somewhere I have old notes that link them together in a reasonable way, but I would have to dig that up later, if you would be interested.

A human universal that you might be missing is the ability to understand things in their context.

Most people do not have the analytical clarity to be able to give an explanation of love isomorphic to their implementation of love; to that extent, they are "confused about love".

This though does not imply that their usage of the word "love" is amiss, the same way people are able to get through simple reasoning without learning logic, or walking without learning Physics.

So I'll assume that people are wielding "love" meaningfully, and try to infer what the word means.

It seems to indicate prolonged positive emotional involvement with an external entity. Other emotions and reactions surrounding this may be dragged in. As everything emotions, the boundaries are not clearly defined, but categories were made for man, not the reverse.

This degree of vagueness may be unnerving if you are more detail-oriented than most people. It is familiarly unnerving to me, as I am pretty detail-oriented. (To readers that are not detail-oriented, a concrete example of being so: searching for a big red thing in store shelves, you notice the big red thing, I scan sequentially the items until I hit it.)

Then the question becomes: Is the category "love" too broad?

First line of argument: if you can put 4 items in two sets of 2 items, you can also put them in a set of 4 items, even if this offends the aestethic sense of @SpectrumDT. This is not a good line of argument, as there is probably a more grounded meaning to the question; it's here just to put it out of the way.

Second line of argument: do some inner mental representations actually match such a broad category? Is this category an unnatural herding of many internal sensations, or is there actually something going on in the mind that naturally brings everything together, leading to humans spontaneously uttering a "love" token in response?

I'll attack this question from the front and from behind.

From the front, humans in general tend naturally to quash things into low-precision numbers in their head, because Von Neumann was right. I know how many favors and tricks you have played on me, and feel if you come out positive. I meet a girl, and as I get to know her, how nice she looks changes based on how intelligent she looks. So it's reasonable that the brain tends to summarize a lot of stuff into a level for "I'm emotionally attached in some positive way to that external entity".

From behind, if humans empirically insist on using this concept, it's probably there for a reason. There must be some naturalness to it.

Third line of argument: would people be better of if, by default, they outclassed their monkey brain in the degree of accuracy they use to think about love? Here I think the answer depends on the intellectual abilities of a person. If you are intelligent enough, at some point it's advantageous to make more complex categories and models. Below some level of intelligence, though, the result of trying to install into someone a more complex love model may not be worth the effort. That person may be better off with a long list of proverbs and heuristics that involve less things at a time, and more broad things, such that pattern matching is easier. Detailed discernment is reached by majority/importance vote over multiple loose patterns.

Conclusion: I overall think love is an adequate abstraction for most people, but not for a minority of detail-oriented and intelligent ones.

(Note: I have the impression the writing style I just used gives a vibe of "I know what I am saying, I'm a PhD in love analysis". I am not.)

I like your "giving / craving / euphoria" classification.

I wonder whether the debates about love are often so confused precisely because in human mind the feelings are not clearly separated. We are prone to the halo effect; for example, if someone is sexually attractive, we might instinctively assume that they are probably also good, smart, etc. (Then some people get burned, and sometimes they overcompensate by making the opposite assumptions.)

But sometimes there are genuine effects of different kind happening all at the same time. For example, I may feel good when I have some kind of (non-sexual) interaction with someone... and at the same time, I may find them sexually attractive (but perhaps I have never communicated this aspect to them, and I have no idea whether they feel the same way about me)... and at the same time, I may feel altruistic towards them. These things happening together have a different flavor than if they happened separately.

So maybe "love" points towards the complex outcome when you strongly desire someone, and simultaneously wish them well, and simultaneously feel happy with them. Some people succeed to get the whole package. Some people only get a part of it, and find the experience confusing, asking themselves whether this is or isn't "love"... and maybe try to fix the wrong part, for example by trying harder to be altruistic, when the actually missing part is that the other person's presence doesn't make them happy.

Well, that would be the whole package for romantic love. The whole package for loving your children includes wishing them well and feeling happy with them and feeling optimistic about their future. Etc.

People are kinda right when they refuse to be more specific, because "love" refers to the entire package, not any of its individual parts. But being more specific can be useful for figuring out why someone fails at love (what part exactly is missing from the package).

Another aspect of Love that's not really addressed here I tend to think of as a sense of 'being on the same team.' When I relate to people I love, I might help them or do something nice for them for the same reasons that Draymond Green passes the ball to Steph Curry - because when Steph makes a 3, the team's score increases and that's what they are trying to do. Draymond doesn't (or at least shouldn't) hold onto the ball and try to score himself unless he has a better shot (he usually doesn't) - points are points.

Whereas when interacting with someone I don't love, I might help them to the extent it advances my own goals, broadly defined (which includes things like 'being well liked', 'getting helped in the future', 'the feeling of doing a good deed').