Why don't US right wingers go to grad school?

As one of you may know and the other will guess, I consider NYTimes writer James Tierney an idiot. In his latest column The Left-Leaning Tower he makes an effort to support the theory that conservatives don't go to graduate school because academia in the United States leans left. First he quotes careful surveys that disprove most aspects of his argument, then he turns to the usual ideologues, who claim that the theory is correct because it must be, no matter the facts, and repeat a few anecdotes about the liberal bias of social scientists.

So, does academia have a liberal bias, or do conservatives have an antiscientific bias? I think one should look for the answers in the science departments. The overwhelming majority of scientists are liberals, in the American definition. An overwhelming majority of engineering and mathematics professors, a fairly conservative (in the sense of cautious) bunch altogether, are Democrats. So are almost 100% of biologists, a branch of science without a political bias if there is one. Even the majority of economists and business professors are liberals.

Thus 1) Republicans do not go to graduate school because they are against scientific reason; 2) John Tierney is a fool. QED.