But when he diagnoses half the world as delusional it is he who is misusing scientific terms.

And 'tis you who misrepresents him. After years on forums like this, I've noticed that people who misrepresent others are very apt to misrepresent themselves also. He does not "diagnose" half the world as delusional. His remarks about delusion are strictly confined to the matter of religious belief. Musket is severely deluded about Sheffield Wednesday, but that does not make him unqualified delusional. Joe Offer believes in God yet he is an intensely rational man with whom a serious conversation is possible. You do not have sensible conversations, on the whole, with someone who is unqualified delusional. You clearly haven't read The God Delusion. What you say about it and Dawkins simply doesn't make sense. Much of what you type seems meant to suggest that you have read it. A clear misrepresentation of yourself, I'd say.