Once again Margaret Wente misses the point. "Don’t we want people who can research and teach, instead of prove [sic] how diverse we are?", she asks. 

Yes Margaret, we want people who can research and teach. And the best way to get the best people is by welcoming people from all walks of life into our academic institutions. This is how we can get the best people from across our entire society. 

As it stands, the best people don't even bother applying. The best people (who aren't white males) don't have allies. The best people (who aren't white males) give up and go elsewhere. The only way to change the situation is to tip the scales in favour of the disadvantaged. 

Will this mean that once in awhile the white male who is actually the best person for the job misses out on an opportunity? Absolutely, but we're playing a long game here. The ultimate goal is societal equality. You can't get there without introducing some temporary inequality to balance out the current unfairness.