Whereas human beings are strong/smart/able enough to care of themselves, hence why many also feel that they're all inherently evil/pieces of shit that deserves what comes to them, so fuck 'em.
on a slightly less directly hostile vector:
in New Orleans, companion animals were left behind to fend for themselves, and wind up being needlessly shot in many cases by the police going door-to-door. Humans got evacuated.
There are a lot more programs and groups in place for the welfare of humans than there are for animals. Also, humans have the ability to speak and spread the word about their condition. Animals don't have that option, so they either have the selfish animal rights people helping them, or they get to die.
I think her reaction post-sentencing has far more to do with her own need to distance herself from what happened and convince herself she's in the right, because how else do you live with doing something like that? Even if it was 'only' a more traditional food animal like a rabbit or a chicken, that's a brutal and cruel way to end a creature's life.
