All cultures? Really? I think not. The barbarians had the same ethics? Nonsense.
Well, ah . . . how are you defining barbarians? Christians and Hebrews have a history of being very barbaric. In the old definition in Europe and Middle East everyone who was not Christian were Barbarians. Yes,by the objective verifiable evidence ALL cultures of the world have a history of consistent morals and ethics. European non-Christian cultures have a long history of evolved Common Law that we inherited in our legal system today.