James Surowiecki's excellent book The Wisdom of Crowds explores, among other things, the value of cognitive diversity. A team will benefit from having people who think differently, have different backgrounds an opinions. While this is obvious, the extent to which it is so is perhaps not. Groups of people who are similar will reinforce each other and produce extreme, and badly wrong, ideas. Groups of people who are different can often be better than even the best individuals within them. For example, if you ask a group of people to estimate the weight of a cow or the number of jelly beans in a jar, the average answer will often be better than the best answer. A crowd of non-experts can be better than the best expert.
Such thinking plainly needs to inform recruiters at businesses and universities. American universities claim to have a diversity policy, but what this means is preferential treatment for some racial minorities. There is no attempt to pursue cognitive diversity. Indeed, given the consistent reports of harrassment of conservative academics, it seems that cognitive diversity is actively suppressed. Even if there is no deliberate policy to achieve this end, it is plain that it is the result - just look at the figures for Harvard staff making donations to political candidates.
A diversity strategy which sought racial diversity as part of cognitive diversity could be defended. The education of everybody will be enhanced if students are exposed to different and challenging views from people with different backgrounds. Racial diversity as a goal while cognitive diversity is being suppressed can have no educational benefit, and needs to be challenged in every way that it can.