Despite their belief, I've seen that they're incredibly big-headed but in a fragile way - see Alex Jones and his agonizing over those fearsome brains that the dread Nerds possess. They fundamentally fear actual intelligence and research, and in that fear they craft scenario after scenario to best explain the fact it seems everyone has some answer except for them. They wring their hands over old prophecies and craft strange little alternate versions of reality because the existing reality is just too scary and disorganized for them - there could be no hand of god guiding this many strange events...but what if there was some overarching conspiracy? Then, for some reason, that would justify the continuation of their God vs. Devil ideology, and they see themselves as ALWAYS on the right side. That they're inherently right and virtuous and the only one who can see the "truth" before their eyes, while everyone else is either in on it or lulled by fluoride.
Its a quick slip and a drop from there into believing everyone else has been replaced by a doppelganger / reptile and things get really ugly after that.