This isn't pedantic nitpicking. Segregation is a deeply evil employment of the state machinery to enforce and persist strict racial divisions in a society.
People choosing to stay near their friends, family, and community centers & therefore the census showing large clustering of self-identified racial groups, is not in any way the same thing.
At the end of the day you just have to be open to figuring this stuff out. If your view is that people were herded into airless ghettos, and then just stayed there with all the lack of opportunity that entailed, because they were making rational free choices to deprive themselves and their children of economic opportunity, you’re living in a fantasy world.
It happens that some neighborhoods are dominated by a certain race / ethnicity, while in others it goes the other way. Unless you want to go back to busing there’s not an easy fix for this problem
If we’re talking about Asians, I agree with you, as far as non-Bob Jones universities are concerned.