Black students perform better when they are in integrated schools. Unfortunately, they tend to bring down overall school test scores so white parents prefer to pull out their own children if the black population gets too big.
My guess is that if a college has too many black students, we won't be seeing Asians or whites sending their kids there as much.
Secondly, funding will dwindle if the black and latino population gets too big. Many of them are low-income and depend on financial aid. This means the school depends on middle class white students to pay or alumni donations. This money will be spread thinly.
I highly suggest that if you have a bright kid, send them to a college where the minority population is low. Let the rich white kids pay for all the facilities, prominent faculty, and other perks all the while your kid gets to enjoy by default.