Why is it a sickness of soul to abuse an animal that's been legally defined as a "pet", but not to define an identical animal that has not been given this arbitrary label?

Eliezer's argument is the primary one I'm thinking of as an obvious rationalization.

https://www.lesswrong.com/posts/KFbGbTEtHiJnXw5sk/i-really-don-t-understand-eliezer-yudkowsky-s-position-on

https://benthams.substack.com/p/against-yudkowskys-implausible-position

I'm not confident about fetuses either, hence why I generally oppose abortion after the fetus has started developing a brain.

Different meanings of "bad". The former is making a moral claim, the second presumably a practical one about the person's health goals. "Bad as in evil" vs. "bad as in ineffective".

Hitler was an evil leader, but not an ineffective one. He was a bad person, but he was not bad at gaining political power.

It seems unlikely to me that the amount of animal-suffering-per-area goes down when a factory farm replaces a natural habitat; natural selection is a much worse optimizer than human intelligence.

And that's a false dichotomy anyway; even if factory farms did reduce suffering per area, you could instead pay for something else to be there that has even less suffering.

I agree with the first bullet point in theory, but see the Corrupted Hardware sequence of posts. It's hard to know the true impact of most interventions, and easy for people to come up with reasons why whatever they want to do happens to have large positive externalities. "Don't directly inflict pain" is something we can be very confident is actually a good thing, without worrying about second-order effects.

Additionally, there's no reason why doing bad things should be acceptable just due to also doing unrelated good things. Sure it's net positive from a consequentialist frame, but ceasing the bad things while continuing to do the good things is even more positive! Giving up meat is not some ultimate hardship like martyrdom, nor is there any strong argument that meat-eating is necessary in order to keep doing the other good things. It's more akin to quitting a minor drug addition; hard and requires a lot of self-control at first, but after the craving goes away your life is pretty much the same as it was before.

As for the rest of your comment, any line of reasoning that would equally excuse slavery and the holocaust is, I think, pretty suspect.

Do you also find it acceptable to torture humans you don't personally know, or a pet that someone purchased only for the joy of torturing it and not for any other service? If not, the companionship explanation is invalid and likely a rationalization.

I agree that this is technically a sound philosophy; the is-ought problem makes it impossible to say as a factual matter that any set of values is wrong. That said, I think you should ask yourself why you oppose the mistreatment of pets and not other animals. If you truly do not care about animal suffering, shouldn't the mistreatment of a pet be morally equivalent to someone damaging their own furniture? It may not have been a conscious decision on your part, but I expect that your oddly specific value system is at least partially downstream of the fact that you grew up eating meat and enjoy it.

Meat-eating (without offsetting) seems to me like an obvious rationality failure. Extremely few people actually take the position that torturing animals is fine; that it would be acceptable to do to a pet or even a stray. Yet people are happy to pay others to do it for them, as long as it occurs where they can't see it happening.

Attempts to point this out to them are usually met with deflection or anger, or among more level-headed people, with elaborate rationalizations that collapse under minimal scrutiny. ("Farming creates more animals, so as long as their lives are net positive, farming is net positive" relies on the extremely questionable assumption that their lives are net positive, and these people would never accept the same argument in favor of forcible breeding of humans. "Animals aren't sentient" relies on untested and very speculative ideas about consciousness, akin to the just-so stories that have plagued psychology. There's no way someone could justifiably be >95% confident of such a thing, and I highly doubt these people would accept a 5% chance of torturing a human in return for tastier food.)

So with the exception of hardcore moral relativists who reject any need to care about any other beings at all, I find it hard to take seriously any "rationalist" who continues to eat meat. It seems to me that they've adopted "rationalism" in the "beliefs as attire" sense, as they fail to follow through on even the most straightforward implications of their purported belief system as soon as those implications do not personally benefit them.

Change my mind?

The images appear to be broken.

Fixed, thank you.