Exactly. Look for the explanation that involves introducing the minimum amount of additional factors. Be especially wary of adding things that must then be countered in some cases.It is much more probable that whatever killed off the ammonite mollusks and whatnot was sufficiently un-picky about what it was killing to take out the dinosaurs as well. One cause is more parsimonious than two.
And when looking at the actions of people and organizations figure that a factor related to what their position appears to be is more likely than one that isn't. It's a very minor leap to figure that an organization might be taking a step (discriminating in favor of disadvantaged races) consistent with their claims about the situation (that said races have been discriminated against.)Universities in general are engaged in a massive drive to recruit and admit students from across a broad range of demographics. This is not because there is a huge need for art history majors to provide art history services in underserved communities. If your hypothesis about med students were correct then there would have to be two unrelated causes that independently result in the same behavior pattern in university admission officers. That multiplies entities unnecessarily. It is much more probable that whatever motivation causes Harvard admission officers to lie about Asian applicants' personal qualities as an excuse to hold them to higher academic standards than students of other races is sufficiently un-picky about its collateral damage to take out medical school applicants as well. "There is a huge need for physicians to work in these communities" appears to be a post hoc rationalization for a policy that was originally adopted for some other reason.
And if it really is because they were discriminated against you have to explain why Asians are doing better than average rather than worse.