From Jonathan Haidt's review on political diversity (or rather its absence) in social psychology:
Conservative graduate students and assistant professors are behaving rationally when they keep their political identities hidden, and when they avoid voicing the dissenting opinions that could be of such great benefit to the field. Moderate and libertarian students may be suffering the same fate.
I asked a while back why there are so few right-wing sociologists (effectively none - although there are a couple of libertarian sorts). It's good to see some real academic confirmation of this as a problem, that having some colleagues who don't automatically blame society's ills on capitalism or neo-liberalism might be a good thing.
Nothing will change though. Most universities will remain hostile places for anyone who wants to explore society from a conservative perspective.