I was mainly talking about LessWrongers who care about others (for not-purely-selfish reasons). This is a much milder demand than preference utilitarianism. I'm surprised to hear you don't care about others' well-being -- not even on a system 2 level, setting aside whether you feel swept up in a passionate urge to prevent suffering.
Let me see if I can better understand your position by asking a few questions. Assuming no selfish benefits accrued to you, would you sacrifice a small amount of your own happiness to prevent the torture of an atom-by-atom replica of you?
We may be using different definitions of "care". Mine is exactly how much I'm motivated to change something after I became aware that it exists. I don't find myself extremely motivated to eliminate the suffering of humans, and much less for animals. Therefore, I conclude that my priorities are probably different. Also, at least to some extent I'm either hardwired or conditioned to empathize and help humans in my immediate proximity (although definitely to a smaller extent than people who claim to have sleepless nights after observing the footage ...
I'm currently unconvinced either way on this matter. However, enough arguments have been raised that I think this is worth the time of every reader to think a good deal about.
http://nothingismere.com/2014/11/12/inhuman-altruism-inferential-gap-or-motivational-gap/