I really don’t want to be the person who says this, but not all white people would choose that… and many people of all races and ethnicities would choose to send their kids to like-race/ethnicity/other characteristic (ie religion) schools. It’s part of tribalism.
I don’t know why we pretend we’re past prejudice though. Those white people you saw screaming at and abusing the Black kids are still alive and many are still in charge of things… or raised children who are certainly in charge of things (like classrooms, school districts, etc). Anyone who thinks we’re past this is beyond ignorant and the epitome of privileged.