Just about everyone who has been through college has stories about crazy professors. I'll tell you a couple of mine.
My first encounter with one came in my second year of community college, in a required course focusing on several thinkers who shaped the modern world including Darwin, Marx, Toynbee, and Einstein. The teacher was an African Sorbonne graduate who wore his watch on the pulse side of his wrist. I had an inkling of his ideological leanings when he criticized our assigned textbook as "too Eurocentric."
There are times when even I question Eurocentrism in traditional histories. As I suspected, however, this professor was merely replacing one "centrism" with another. I could feel his frustration as he looked for openings in the assigned material to tell us about his beliefs, which included the idea that much of Ancient Greek civilization was "stolen" from black Egyptians. It wasn't easy for him, since he was assigned to be teaching us about DWEMs (Dead White European Males). I was immune to his digressions because on the first day, I had gone to the library and borrowed a copy of Mary Lefkowitz's Not Out of Africa, which debunks Afrocentrist claims about history. I learned more from that book than I did from the entire course.
He was only a moderate Afrocentrist. At the extremes is Professor Leonard Jeffries of City College in New York, who holds that mankind is divided into "ice people," comprising those of European descent, and "sun people," comprising everyone else. Ice people are violent, materialistic exploiters, while sun people are kind, compassionate peacemakers. Dr. Jeffries also maintains that Jews financed the slave trade and continue to use Hollywood to promote black subservience. It's like he took the Nazis' master-race theory and flipped it around. Around the Jews, that is.
Later on, I got an American history professor who was almost as weird as the Afrocentrist guy, though in a different way. He looked like a character out of Roald Dahl: slight build, pointy nose, pencil-thin mustache. The oddest thing about his appearance was his hair. "Never trust a professor with strange hair" should be my motto. He looked like he would have been an ordinary bald man except that he had a big clump of hair resting on top, almost like a cockatoo. Bad use of monoxodil, I thought.
On the first day, he mentioned that previous students had complained he hadn't made his teaching relevant to the current times. He promised not to make that mistake with us. He kept his promise. For one thing, he had a relentless obsession with Bill Clinton, whom he considered the most corrupt president since Nixon. (This was a while before the Lewinsky scandal.) Throughout his lectures, he kept throwing in comments about how "Slick Willy" and his wife were letting the country go to waste.
He didn't seem to recognize any boundary between fact and opinion. FDR, he taught us, was a great president, though not because of his liberalism. Truman was overrated, Eisenhower was underrated, and Vietnam was unwinnable. The prof's most fervent belief was that there was a conspiracy behind JFK's assassination. He wasn't sure of the nature of the conspiracy, he just knew beyond any doubt that there was one. And he let us argue our favored conspiracy theory on the final exam for extra credit. Accepting the findings of the Warren Commission wasn't an option.
For several years afterward, I went mad trying to read up as much as I could on the stuff we had covered, which I felt had been tainted by the guy's political and ideological proclivities. I eventually concluded that apart from his hangups about Clinton and JFK, he was reasonably fair and accurate most of the time.
I'm not implying these two professors were in any way representative of my overall college experience. After I transferred to U. of Maryland, I no longer met any ideological fruitcakes. A few of my professors there articulated liberal political views in front of the whole class, a practice I considered unprofessional (at least in non-political courses). But there was relatively little weirdness and flakiness. Yet the fact I encountered this sort of thing at all is significant. These are the kinds of experiences you hear and read about, and can't believe when they're actually happening to you.
P.S. For those who may not be aware, the picture at the start of this post is of the late comedian Sam Kinison playing a crazy professor in this scene from the 1986 movie Back to School.