This was a profound insight that a colleague told me this week.
Professors are drawn mostly from the nerd tail of the distribution. We are more likely to to see class as the best place to find friends and allies on the road to understanding the world.
The modal Centre student, by contrast, finds friends in their social groups - teams, clubs, first-year halls, and, especially, Greek organizations. They often do not learn the names of their fellow students in a class. They do not see class as the central arena for the main drama of college.
I don't know whether this is true of most colleges. I think that it was less so at Swarthmore, where I was an undergraduate, and Brown, where my colleague studied. Even there, though, class was not the main friend maker for everyone.