Mr. Rock is right and he is making an argument that has been made for decades. It is an argument that dates back to, at least, the time of John Carlos and Tommie Smith, influenced by Harry Edwards, and their demonstration at the '68 Olympics.
As bad as it is in the NCAA it is worse here in Canada. The NCAA mandates that kids go to class and graduate. You may check out grad rates for all Division I, II and III schools in the NCAA at their website. They compare the grad rates of non athletes to athletes. You may cross reference by race, sport, gender and nationality to get a better/worse picture of what is what.
Canadian Intercollegiate Sport offers no such resource I contacted their predessor, the CIAU, early in the century and they refused to even consider publishing grad rates, citing privacy issues. I call bullsh*t.
CIS athletes unlike most of their U. S. counterparts, do not not get full rides either. Or partials.
Another thing that the NCAA strives for is gender equity. Coz, under Title IX, which came in during the administration of Archie Bunker's favourite President, Richard E. Nixon, if you spend a buck on a boy in an educational setting you have to spend a buck on a girl. That is why there has been an explosion in women's hockey, soccer, hoop and so on in the last couple of decades here and south of the border. The CIS doesn't have to offer gender equity.
Good thing Mr. Rock isn't studying on Canadian college sports, eh?