I actually think primatology is quite useful here. We aren't that different from other primates. We selfishly attach extreme morality only to things that impact us, which we would never do when we analytically study primates doing the same kind of thing (stealing and killing). To be frank, your kind of comment makes me more suspicious of human morality itself (as a social tool to mask resentment or overcome collective action problems towards some kind of aggressive action) than it does of humanity.