Hmm. Reading your comment, I kind of get why my experience was probably pretty different. Christianity was rarely the focus of the conversation and I doubt if it started to occur, anyone would tolerate any proselytizing. I went to a community college, so even "enrichment" classes were full of people with little time and little money to feel like their attention was being wasted. I personally used to absolute detest people who derailed classes and the people who did it were often repeat offenders. Any time their hands would shoot up there really would be a collective groan from other students. I hated most people who'd waste class time to squabble with the teachers over assignments and grades, as if office hours didn't exist or something.

That said, when religion was discussed, it was brought up as part of the lesson by the teacher. A real good example is, in my Asian History class, besides a whole week being devoted just to focusing on religion, the subject was brought up often from everything from philosophy, to governance and politics, to economics, trade, and population shifts. It was some darn fascinating stuff.

Had I had your experience, I'd have hated it too.