People are social animals (most of the time) just like many of the various species that operate as a group. Lions, meerkats, dolphins etc.
So long before man could speak, or write books. there were rules of intereraction. of course there were bad eggs (just like now). but the foundations were set long before man invented religion and God! (sorry couldn't help that one!)
morality itself is debatable on finer issues. It's nothing more than arrogance though to try and claim some ownership by any particular group. might even be immoral..?
