Colleges once used to be a diversity of ideas. Not so much anymore. Universities are now a incubator for Progressives when it comes to professors. I’ve had several scoff at this statement but some big data has come out on this just to reflect the trend. The Heterodox Academy had this breakdown. Read full article here:

American universities have leaned left for a long time. That is not a serious problem; as long as there are some non-leftists in every field and every department, we can assume that eventually, someone will challenge claims that reflect ideology more than evidence.

But things began changing in the 1990s as the Greatest Generation (which had a fair number of Republicans) retired and were replaced by the Baby Boom generation (which did not). As the graph below shows, in the 15 years between 1995 and 2010 the academy went from leaning left to being almost entirely on the left. (The 12% in the red line for 2014 is mostly made up of professors in schools of engineering and other professional schools; the percent conservative for the major humanities and social science departments is closer to 5%).