A number of attempts have been made to construct theories that show why academia is overwhelmingly leftist. Some of them are quite amusing, such as the theory that liberals are just so much smarter than the rest of us. Of course conservatives don't want to work at universities. They're just so stupid.

The hard fact is that the environment at the universities, including mechanisms for acceptance and advancement, make it almost impossible for overt conservatives to get and keep positions, gain tenure, or have any influence on how things are done.

The article contradicts itself:

Intentional discrimination, one of the most frequent and volatile charges made by conservatives, turned out not to play a significant role.

But a couple of paragraphs later:

The mismatch between schooling and salary complements a theory that the Harvard professor Louis Menand raises in his new book "The Marketplace of Ideas." He argues that the way higher education was structured by progressive reformers in the late 19th century is partly responsible for the political uniformity of today. In the view of the early reformers, the only way to ensure that quality, rather than profit, would be rewarded was to protect the profession from outside competition. The tradeoff for lower salaries was control; professors decide who gets to enter their profession and who doesn’t.

Maybe low salaries encourage leftist thinking. Imagine thinking yourself to be among the world's intellectual elite, but having to watch college dropouts make billions.

It's also amusing to see the lists they put in the article:

Journalism, art, fashion, social work and therapy are dominated by liberals; while law enforcement, farming, dentistry, medicine and the military attract more conservatives.

Note which occupations are "fuzzy" subjects, and which require you actually know some objective facts about reality.