Even then people will look for a reason to hate. The light brown skinned people with straight hair will probably look at those with curly hair as a different race at that point.

Remember that in Europe when it was Germanic people against Kelts they considered themselves different races because they had different languages and cultures. To a Nigerian they'd look the same except one side tended to red hair and the other to blond - though both sides were mixed in that regard too.

Although I wish we could,I don't think people will ever get past that kind of bias, sadly...