>Correct me if I'm wrong, but the fact that colleges always say they're looking for "diversity" is a blunt admission that they're their reason for looking at race is "diversity" (a.k.a. affirmative action), not to determine leadership skill.

It can certainly be read this way, but it's not obvious that this is so. Diversity creates an atmosphere that will most likely mirror the world in which these future leaders will be required to navigate. That in itself is enough of a justification for diversity, assuming their goal is to educate future leaders. Also, there is the fact that leaders of ethnic groups tend to be of that ethnic group, so maximizing some proportion of diversity is increasing that schools chance of educating a future leader.