Instead of Indoctrination
On Protein Wisdom, Scott Eric Kaufman is defending academia against the charges of indoctrinating students and flunking qualified conservatives. There's more than one way for a professor to lean left. I suspect the most important way is simply to neglect to correct leftist misinformation.
Misinformation is frequently passed down from one generation of students to another. As a result, students learn that Christopher Columbus discovered the world is round, that astronauts are weightless because they're beyond the Earth's gravity, that marijuana smoke does not contain carbon monoxide, that religion is somehow opposed to rational thought, and that plutonium is the most toxic substance on Earth. All that is needed is for the professor to not bother correcting the currently-trendy parts of the misinformation.
In some cases, all that is needed is a delay in correcting the misinformation. Once an opinion has become sufficiently entrenched, any professor who tries correcting it will be regarded as having sold out to “The Establishment.”