However, inter-racial sex will. The Cultural Concept of Race Skin color is but one characteristic out of many that is available for use in a system of differentiation. My hunch is that pointing out the differences between your group and their group has been a very common practice amongst humans throughout history, and throughout a considerable amount of prehistory as well. It may be an indicator of alienation, but it is just as much if not more likely an indicator of a desire to distinguish and differentiate amongst your fellows and fellaheen. A free people will always think of themselves as different from those they perceive not to be free.
Skin color is an easy way to identify one group from another.
It makes sense in a territorial kind of way. The two opposing teams wear different colors, or play shirts and skins. In New York City, the common gang practice is to match the colors of the caps on the crack vials they sell with the colors of the gang. They are at those times without their color. Differentiation and status are perhaps universal social desires.