If you truly think that the top 2.5% of black students would be "out of place" at Harvard then you have a completely invented mysticism of what it means to go to Harvard.
https://my.vanderbilt.edu/smpy/files/2013/02/DoingPsychScien...
What was this highly predictive test? It was, quite simply, taking SAT at 11-12 years of age. SAT is really good test, and is highly predictive of academic success, its biggest flaw is that it is too easy for those at the top of distribution, but that can be ameliorated by administering it earlier than typical.
> If you truly think that the top 2.5% of black students would be "out of place" at Harvard then you have a completely invented mysticism of what it means to go to Harvard.
If 2.5% of all black students were of Harvard quality, then something like 16% of white students would be, which is something like 3 kids in every high school class. Harvard can afford to be much more selective than that, and in fact it must be so to keep its brand.
Regardless of how selective they are with admissions it also doesn't mean that a large chunk of the people they rejected wouldn't have also done fine there.
Arguably it's much easier to get good grades at Harvard due to grade inflation if you are a good student (which you are by definition if you are at the top of your class) than at state schools.