Once you see it, you can't unsee it. Once the spell is broken, it becomes apparent how ridiculous it all is. The default is disbelief, but we suspend our disbelief like any good audience member and accept the reality which is presented to us. But when we stop and realize that real life is real life, not the movie, suddenly the propaganda looks like the sloppy propaganda that it is.
Yep. You ever watch jaydreamerz on youtube? He has a series called "truth in movies".. Good stuff.