I heard somewhere that extremists are more likely to go to the opposite extreme than to moderation.
Yeah, that tends to happen when people consider religious claims seriously. Moderation is the land of compartmentalization and going-through-the-motions.
Because Fred Rogers was such a fanatic. This may shock you, but somebody can be devoutly religious without being a frummer.
No, they really can't. Religion claims a monopoly on absolute truth, and when your scriptures have poison in them, you either:
a) reject the religion wholesale
b) follow it to the letter
c) compartmentalize and try not to think about the glaring contradictions
A and B are serious approaches. C is mainly done only for social approval.