There are, but Harvard is not the only one competing for them. Once you consider all top schools, the population of ADOSes who can make it based on academics is really tiny: given the fundamental constant of sociology being 1 sigma difference between white and black Americans, given how normal distribution works, the difference in figures at the top of distribution is enormous.

For example, if Harvard only wants to admit people 2 sigma above median, by 68-95-99.7 rule it will be 2.5% of white applicants, but 0.15% of black applicants. That’s 16-to-1 even before you adjust for the fact that non-Hispanic whites are 60% and blacks are 13% of population, after which you get something like 75 qualified whites for each whites. Add to that Hispanics whites, who, while overall having lower academic achievement, are not nearly as low as blacks, and Asians, who have even higher achievement than whites, you’ll easily get something like 100 to 150 qualified non blacks for every black applicant.

Even more concretely: there are something like 2 million freshmen every year. 2 sigma cutoff means only 2.5% of them qualify, which is only 50,000 people. 1 in 100 means only 500 blacks qualify at above 2 population sigma. Then you have all Ivies and other top schools compete for these. So yes, you can find 300 blacks at 2 sigma cutoff, but Harvard won’t get all of those. Thus, Africans.