That is why I said, I think most people handle this by telling themselves that animals aren't "intelligent" beings at all, and are mostly emotionless stimulus-reaction automatons.
I don't think Amodei is probably absurdly evil (in the way most people conceptualize evil), I think his paycheck just relies on a different incentive than his concerns about AI ethics. Like most people who end up doing bad things (not saying he is necessarily, but were he to), it's a matter of convenience, selfishness, or simple avoision of considering implications too deeply.
I especially think one aspect of normalizing/rationalizing actions with (potentially) harmful consequences is telling yourself things like,
"well, I can't put the genie back in the bottle even if I wanted to"
"someone is going to do this if I don't, and they'll be even less ethical than I will" (the change-the-system-from-within fallacy)
"If I ever discovered this was really harming someone, I'd stop"
"There's a line I won't ever cross, and as long as I stick to that, I won't fall prey to the worst impulses"
These are things people believe are self-imposed limits, but they're actually a means of convincing yourself that whatever you're doing... isn't whatever bad thing you've set on the other side of the line.