>>13
Sure, if moral relativism meant that. It doesn't, of course, but at least you tried.
Moral relativism only talks about differences in cultures. This argument says that because their are different morals between different cultures, there is no all encompassing moral philosophy between the entire human race that everyone ought to follow (the universal morality). This argument is flawed, as the conclusion does not follow from the premise. Just because there are difference between peoples doesn't mean there isn't in fact an actual objective morality that people should follow. It would be like saying that because some people don't believe that the earth revolves around the sun, then the earth doesn't revolve around the sun. The difference with that and objective morality, though, is that the reality of it is still up in the air.