I've been thinking about a line by one of my students at Miami University (Oxford, Ohio), probably in the late 1980s. I've forgotten what the context was, but there was a context; this wasn't off the wall. Anyway, the student said "The most important thing I've learned at college is, 'Not everybody is Catholic.'" And this was at Miami U at Oxford, a school with a lot of conservative Irish (and some Polish) Catholics.
Not everyone is Christian or monotheist or theist either.
Good for him. However woefully ignorant many American Christians are of their religion(s), however much the US of A is a (revolutionary, secular) Republic, and not a nation, Christian or otherwise — there's still an issue with us of "Do fish know they're in water?" Much of American culture is strongly inflected by Christianity, and the Christianity of the Western, Roman Church and its dissenting (and agreeing) descendants. E.g., what I as an outsider see as an otherwise strangely strong concern with beliefs and attitudes and "state of mind" is understandable among people who must seriously deal with the line "By Faith and Faith alone shall ye be saved" (unless it's irresistible Grace or the Sacraments of Holy Church).
That may be the most important thing going away to college teaches. The Truth is out there, but we see it from different angles and with different suppositions, right down to differences in training in different sub-fields. (The one time I did real science in what came down to a classic physiology lab, our data sets were a few dogs or maybe a few dozen rats. Things were different in microbiology, where we usually dealt with bacteria and such by the millions and billions. You asked different kinds of questions.)
Back in the 1980s, the State of Ohio was still pitching in a bit to subsidize the education at public schools like Miami of Ohio residents; with this student, the taxpayers got their money's worth.