The Blind lead the blind!

I have a question, why do we allow our religious leaders to use the ignorant to their favour? Why would a pastor be casting out demons just cos he is ignorant of the science of man? Why would a pastor be allowed to label a child with autism as demon possessed? I wouldn't even begin to dignify these with an answer so much as to say that if we have pastors who consider Harry Potter's writer as a witch are wizards themselves.