Thank you for sharing this fascinating story. I do think a lot of us self-segregate. The majority of my friends have never come from one race for most of my life--many of my friends are white, Black, Hispanic, East Asian, etc. But these days, I've noticed I'm hanging out a lot more with other minorities compared to white people. And at my last work place, I definitely bonded with other minorities for that reason. So it's something to watch for.
To most of my white friends, I'm their only minority friend and that's scary.