Humans are clannish, that is human nature. Over the course of time, races intermingle and blend--history shows that.
The problem is the attitude. Look at Rwanda. This is a 100% Black country. Yet we have genocide? Why? Well for one thing the Tutsis are taller than the Hutus. For another, the Tutsis were a ruling class. Race? I don't think so.
How about Cambodia. 25% of the country is slaughtered. Why? Race? I don't think so. The people who had religion or education or who had been abroad were slaughtered. They were all the same race.
People of the same race are clannish and will slaughter each other. Such, I am sad to say, is human nature.