It seems to me that when I was at Walt Disney's "Its a small world after all," I got the impression that he was saying that people differ in dress, but all biological differences are irrelevant. [the song itself is from Mozart]

This came up because of my question about elite schools. The idea of my learning partner was that the USA is not elite enough. 

This seems to me to relate to the fact that most species have changed within the last 10000 years And the human species is also evolving into different species. Perhaps many different species. But at minimum we can see the major differences with be three. Whites. Blacks. Muslims.

The differences in species start with race and can come about by one groups being separate from another group for enough time. It does not matter why one group is separated from another. But it is that separation that causes the species to diverge.
This may not sound like Sunday school, nor John Locke. But it is simple biology.