I guess there are a few possibilities.
That part of your brain is defective so it is already closed off/shut down at birth
You make a conscious decision to ignore it so you can be adoringly worshipful of the nutjob
You are so enamored of and awed by someone you AUTOMATICALLY close down your brain and join the bandwagon of like-minded worshippers.
Some evil deity puts a spell on you and brainwashes you to see what isn't there and not see what is
Can they all be in operation simultaneously? Mebbe.
