Why are these 2 books so widely refered to among various "high magick" places? The KOS has been proven to date back only to the middle ages, thusly, it was not really written by King Solomon. The Necronomicon is a Lovecraft creation and nothing more. Though yes, I know there are "real" copies of the necronomicon around that say that lovecraft was lying about its existence, it has been proven that this was simply a fake produced in the 1970's. So again, why are these books so highly regarded as ancient magic texts of old, when they don't even date back to their supposed creation? By the way, I'm excluding uses in chaos magick. So besides that.
I have no knowledge on this issue, so I'll say only this: maybe the people don't care, because they believe the books to be true. If a Christian found out that the Bible wasn't written until the year 300, I doubt it would change their faith, even though that calls into question the veracity. If a Buddhist found out the Buddha had never existed, I bet they wouldn't care and would still meditate, because the idea is what counts, not the book or the source or any of that. Just my $.02