The problem is you get triggered if someone merely recognizes the fact that different cultures have different moral systems. Then you start screeching about pedophilia or slavery or whatever and derail conversation. Can you please stop?
Agreed. But that doesn't mean they don't occur naturally. At doesn't mean all societies will end up with the same morals.
It's fine to argue that some moral systems are better, and some are worse. It's fine to think the that your moral system is the best, and it's fine try to persuade others of that.
Are you trying to argue here that morals come from a supernatural authority? Because that's where you lose me. Especially if you want to claim that as justification for forcing your morals on others.