It is a falsehood to claim the money was made of free labor.
1) Athletes receive massive benefits that in almost all cases exceed the value brought in, so no not free
2) Labor is a classification. College athletics is not classified as labor. Stating that it is currently is incorrect.
3) The vast majority of value in college sports is generated intrinsically by the institutions/communities themselves, not the athletes. Consider that if the athletes in say, college football, left and formed a new league, that league would have little to no value. Yes there is a symbiotic relationship between athletes and schools here, but the main driver of value is from the schools. It isn't anti-athlete to point this out. It is just the reality of it.