Healthy people can instinctively tell that homosexuality is disgusting.
If a man thinks it's hot to eat the shit out of another men's hairy asshole, he clearly has a very different set of values to him which healthy people cannot ever hope to come to understand.
As such, he cannot be expected to behave orderly, because if fucking another man in the ass seems hot to you rather than revolting and wrong, why would murdering a child be any different?
An alien morality system will only ever coincide with human morality by pure coincidence.