Breh, homogeneity and separation have a whole other set of problems... human beings are flawed and societies will always have flaws...
What i mean is that if you are going to pick and choose the members of your society (blacks or whites only to prevent racial conflict), what is the point of picking by race, when you can pick by intelligence and other metrics
The most thriving peaceful societies around today are the most homogeneous ones
Have you ever heard of social issues in South Korea, Iceland or Japan? Me neither
Meanwhile, The Middle East, Africa and Latin America are all genetically diverse as can be and they cant unite/get their shyt together for anything