that none of this really matters at all.
College and professional athletes make up such a small sample of the population at large that you just can't expect the percentages to be equal. It's simply a stupid study to even consider. MLB doesn't have a lack of racial diversity problem. It has a long boring games, steroid, and terrible commissioner problem. The NFL doesn't have a racial diversity problem, it has a labor dispute getting in the way of one of the most successful businesses in the world. The NHL doesn't have a racial diversity problem, it just isn't played anywhere south of where it's cold as crap and no one cares.
And you're right. Imposing some idea of athletic talent based on skin color is ridiculous and prejudiced. And really, the racial makeup of high school sports is probably more like the actual population. But to expect a league with 1,600 players to represent the racial makeup of a population of over 300 million racial makeup is simply ridiculous. To even expect it in college is asinine. How many players in D1? 117 or so x 80? Don't even know the roster sizes actually, but using those numbers, you've got almost 9,400 D1 football players. That's 0.003% of the population. Statistically insignificant.