I guess I see things differently than you. There are many who prefer to be with their own race not just white people. I always see Chinese people in groups with other Chinese people for example. There are tons of interracial couples now. I was was married to a black man many years ago. I see a lot of mingling between races, too.
No, I know that you are right. There are people other that whites who like to live amongst 'their own'. And, yes, mixed marriages and much more common than in the 'old days'. I haven't lived in the US for 16 years and probably don't get enough of an idea of how things are now on short annual visits. There is racism in the UK but from my perspective it is much less. I read somewhere (might have been here) that someone was complaining that there are so many different races and ethnicities in London. That is a reason to LOVE London, not complain. It's like a mini-world with people from every country.
BTW, I had a boyfriend in the 80's for several years that was Black. My sons loved him, but my family who taught me as a child that all people are equal, did not want to meet him. Hypocrites.