Not exactly a one-word answer to that one. Should they be jailed merely for the fact that they were religious fanatics? Nope.

But...if they're religious fanatics AND other religious fanatics of the same faith were engaging in terrorist activity that was driven by said fanaticism AND the men in question had been in contact with proven terrorists...

...then yeah, lock'em up and schedule a probable cause hearing. It was the lack of those hearings that made detentions in Gitmo illegal.