Posner's examples offer strong support for the sharp limits on free speech in American universities. Another indication is the recent petition signed by hundreds of Stanford faculty against the appointment of Donald Rumsfield to a very part-time position as a Distinguished Fellow of the Hoover Institution, a think tank that is part of Stanford (I am a Fellow of Hoover). According to this petition, Rumsfield is not worthy of Stanford, despite his having served his country twice as Secretary of Defense, as a Congressman, and at several other important government positions. He was also a very successful head of two companies, and he has an intellect that is far superior to many professors at top universities.
Although there are numerous exceptions in economics and political science departments, business and medical schools, and elsewhere, the majority of faculty is considerably to the left of the general population. They are at the forefront of the politically correct movement. This is why Larry Summers ran into the problems that led to his resignation as president of Harvard. However, college faculties are not the only promoters of political correctness. Many print and TV journalists, actors and movie directors, and others involved in more intellectual and creative pursuits have the same views. Why is this so?
I wish I had the answer; I don‚Äôt, so I will speculate about possible reasons. In his 1950 book, Capitalism, Socialism, and Democracy, the great economist, Joseph Schumpeter, discussed exactly this question when asking why intellectuals were so opposed to capitalism during his time? His answer mainly was that businessmen do better under capitalism, whereas intellectuals believe they would have a more influential position under socialism and communism. In essence, Schumpeter's explanation is based on intellectuals' feeling envious of the success of others under capitalism combined with their desire to be more important.
I do believe that Schumpeter put his finger on one of the important factors behind the skepticism of intellectuals toward markets, and their continuing support of what governments do. Neither the unsuccessful performance of the US government first in Vietnam and now in Iraq, which they so strongly condemn, nor even the colossal failures of socialism and communism during the past half century, succeeded in weakening the faith of intellectuals in governmental solutions to problems rather than private market solutions. Since their basic hostility to capitalism is largely unabated, but they are embarrassed to openly advocate socialism and very large governments, given the history of the 20th century, intellectuals have shifted their attacks to criticisms of the way they believe private enterprise systems treat women and minorities, the environment, and various other issues. They also promote political correctness in what one can say about causes of differences in performance among different groups, health care systems, and other issues.
I believe considerations in addition to simple jealousy and envy are behind the opposition of intellectuals to capitalism. A belief in free markets requires confidence in the view that both sides to a trade generally gain from it, that a person's or a company's gain is not usually at the expense of those they trade with, even when everyone is motivated solely by their own selfish interests. This is highly counter-intuitive, which is why great intellectuals like the 16th century French essayist, Marquis de Montaigne, even had a short essay with the revealing title "That the Profit of One Man is the Damage of Another ". It is much easier to believe that governments are more likely than private individuals and enterprises to further the general interest.
Of course, the evidence that has been accumulated since Schumpeter's book gives good marks to free market systems in promoting the interests of the poor and middle classes, including minorities. And examples abound of corrupt and incompetent government officials who either mess things up for everyone, or promote these officials' interests. This evidence has impressed the man and woman in the street, but intellectuals are more removed from the real world, and tend to rely on and trust ideas and intellectual arguments.
This would be my primary explanation for the questions raised by Posner about why faculty (and I add other intellectuals too) have become further to the left of their students and the general population. In effect, intellectuals have changed their views far less than other groups in response to the evidence. While intellectual opinions have stood rather still, the general population has moved their thinking against government solutions and toward solutions that use markets and other private transactions and relations.