I think it’s really more of a sociology thing. Like, it’s pretty well accepted that our natural inclination towards fairness is not from a biological drive, but because we would want to be treated that way. The best way of ensuring that is creating a society where that is the norm. Mankind decided that killing others is wrong because we don’t want to get killed ourselves. If we think stealing from others is fine, we have no redress if someone steals from us.
When I was young, I noticed that the some of the Hammurabic Codes shared a lot in common with Christian teachings. I brought this up to my dad and he said “Yeah, where do you think Hammurabi got the idea?” Now, obviously, he’s got his timeline confused, and even as a small child I could do that math and knew the royal edicts pre-dated the 10 commandments and are of a completely non-religious nature. Groups living together need fairness to prosper.
Evolution, however, tends to lean more towards the strongest surviving. Evolutionarily, we need our genes passed on. Sure, we might manage to procreate before we die, but then we’re not around to protect that lineage. Lions are a good example of that problem. If a rival male takes over your pride after killing you, they will also kill all the cubs. Presumably so only their genes are the ones moving on. That is the evolutionary drive. Wolves, however, are much more social creatures. They function as a group that doesn’t necessarily need to be related and they make decisions similar to how we would expect our own group behaviors. If one of the pack is hurt, they don’t leave it behind to die, they protect it and even leave them behind with the pups to heal when they go out on hunts. But this only extends to their pack. Anything outside the pack does not get that consideration. It’s only in groups where being grateful and kind is an advantage.
Sociology is still a science though! A very good reason to follow those precepts.
Oh man, and that other poster thought they were rambling… I get real wordy when the Adderall kicks in first thing in the morning.