Re: "university education"
I have my own hypothesis on this: Education and exposure to wider ideas makes it more difficult to reconcile the contradictions of moderate religion.
Moderate religion is full of self-contradictory elements. You need to believe that all followers of other religions are going to burn in hell forever, but also respect their freedom of religion - even allow them to raise children doomed to burn, when the compassionate thing would be to kidnap them for their own good. You need to believe in a paradise afterlife, but still value self-preservation. You need to believe you have a book with the words of the all-powerful creator, but only bother to skim through it once or twice a year. You've got to believe that this verse forbidding murder is a divine moral mandate of unquestionable authority, but this verse a little later in the book requiring stoning the gays is safe to ignore. You've got to tolerate the preachers of other religions, even when you know that they are dragging people down to hell with them.
There comes a point when it's too hard to reconcile what one believes they believe with how one acts - and at that point people are forced to either admit they were lying to themselves and abandon the religion altogether, or embrace it to the fullest possible extent become an extremist.