I think the overwhelming majority of people in the US who are 'working 60-hour weeks, at jobs where they have to smile and bear it when their bosses abuse them' are also consuming large amounts of luxuries, and I think it's reasonable to conceptualize this as 'they are working longer hours than they have to in order to consume lots of luxuries'.

May I ask you two questions?

1. Can you please list several things that you consider luxuries and which you believe these "poor" people spend a lot of money on?
2. What evidence (and how much) do you base this on?

Yes. Thanks. Good explanation.

which sucks incredibly and is bad.

Your wording here makes me curious: Are you saying the same thing twice here, or are you saying two different things? Does the phrase "X sucks" mean the same thing to you as "X is bad", or is there a distinction?

Realizing that your preferences can and do develop obviously opens the Pandora's box of actions which do change preferences.^[1] The ability to do that breaks orthogonality. 

Could you please elaborate on how this "breaks orthogonality"? It is unclear to me what you think the ramifications of this are.

And sometimes communities do in fact have explicit “preferences” that will cost people status just by having different ones. It might even be costly to find out what those diffuse preferences are, and especially daunting for people new to a community.

Could you please give some examples of this? It is unclear to me what kind of things you are talking about here.

or you don't really know yourself well

Why do you think that?

What I mean is that the distribution has a crazy variance (possibly no finite variance); take two "opportunities to do good" and compare them to each other, and an orders-of-magnitude difference is not rare.

Do you mean the differences between the expected utility upfront? Or do you mean the differences between the actual utility in the end (which the actor might have no way to accurately predict in advance)?

I also think that in any kind of complex system, monocultures are fragile.

This is a valid point. But the world is far from a monoculture. Even if all currently endangered languages die out, we will have plenty of cultures left. 

If the world ends up with less than, say, 100 languages, then I agree it starts to make sense to preserve them. As it stands now, I think we have more than enough cultural diversity, and keeping tiny minority languages and cultures alive is not worth the opportunity cost.

It can be too slow to catch up to rapid change, but then in that case one of the things you want is a diversity of cultures for selection to act on.

Is this the problem that you are trying to solve by preserving cultures? Make the human race as a whole more resilient in the face of rapid change?

Is this really the reason why you think culture is important? Or is it a rationalization? 

I am skeptical for two reasons:

1. Your argument about rapid change seems extremely different from your argument in the grandparent post where you talked about literature and philosophy, Aristotle and Chaucer.
2. Do you think that preserving a bunch of tiny cultures of a few hundred people (many of whom probably live in poverty) is really going to help make the human race more resilient in the face of rapid change?

In those words it sounds like a bad thing, but look past the words and is it, really?

In my opinion, yes. That is why I posted the question.