The Racetrack vs. College

What does the racetrack have that colleges desperately want?  Diversity.  Real diversity.  You see white frat boys, old asian women, middle aged black men, mexican families...as close as you're going to get as a true sampling of America.  The universities idea of diversity are taking a few token blacks and hispanics from the suburbs to throw in with the white/asian/jewish population.  Why do colleges expend such enormous resources to get "diversity" when they could easily achieve the same by just going to the track and picking people from random to attend classes?