It’s not the case that every single black applicant gets admitted before a single white/Asian applicant does. The point is that it’s much, much easier for a black applicant to get admitted.
A black applicant with GPA and MCAT scores in the lowest bucket still has a 56% chance of admission. That’s on par with an Asian applicant who has GPA and MCAT scores in the highest bucket.
Maybe there are other factors, and they're correlated with the buckets being used here?