a sprinkle of diversity

In my experience, even the most liberal leaning individuals do not desire absolute, uncontrolled diversity in their social lives. They want a sprinkle of controlled diversity, just like Harvard trying to maintain a certain percentage of internationals in its student body. (When Harvard campus got dominated by Jews, the administration introduced non-quantitative arbitrary aspects to its admission process.)

I remember how bodyguards of a hip jazz club in Cape Town bounced black people once there were already "too many" black people inside. If you ask to the white patrons, they will all find this behaviour disgusting and racist. But if you remove the filter, most of them will leave.