If I found you a dozen extra violin-playing science hopefuls with high scores and GPAs who were black you and I both know exactly what would happen. The "meh, they don't have a hook" functions as a post-hoc neutral justification of a policy whose stated goal and naked application is to discriminate on the basis of race. It's as transparent a fig-leaf as "We can't admit blacks, they might only speak Ebonics, yo!" would be if you were staring at a transcript which showed multiple awards for competitive forensics, a 4.0 GPA, and a role as Iago that got written up in the NYT. It is also, verbatim, the justification of ethnicity-conscious "holistic" admissions processes which were adopted at Harvard in the 1930s with the explicit, documented aim of keeping "the Jewish problem" to a manageable level.
You can only admit so many violin playing science hopefuls.