If critcal = critical then in the case of animal mutilation its a simple matter of there being no possibility of informed consent.
How would most people feel about somebody that got off by watching cats get legs amputated? Ask yourself deep down how you'd feel about that. Are you going to argue that that this is somehow fundamentally different?
I have no problem with what sane people agree to do to each other but animal cruelty just sick - although admittedly a cat with no legs could double up as a pet and a draft excluder.![]()