I did that with mormon preachers one time because I was seriously bored. Doesn't seem to work. They can repeat themselves infinitely, especially if faced with contradictions.

I think there's a crucial difference with the nazi officers: the nazi officers were more or less sane guys in an environment where they had to profess a belief in belief and rationalize other's errors of thought; they didn't really face a lot of alternatives, and furthermore had pretty damn good deep survival related reasons to drop their beliefs. The religious folks are self selected true believers, or children of self selected true believers, and however strong was the propaganda it is but a drop in the ocean compared to upbringing. Some believers genuinely possess the failures of thought that create their beliefs; some merely imitate this; and among the self selected there's much more of the former.