EVERY cult begins with normal people and then gets them to believe what no normal person would believe. In truth, all religions have at one point or another spawned cults who turned normal people into kool-aid drinkers. Christianity included. But Islam is reading its kool-aid right out of the book! I am not surprised that some Muslims believe that bin Laden had nothing to do with 9/11. Believe me, there are plenty of Muslims that believe he did and are cheering for another one. No doubt many Imams tell their (American) flocks that Islam is peace and it is impossible for Muslims to do any of these bad things. I would expect nothing less.
I understand intellectually that you are right. I just am having feelings of unreality right now. He was just so much like a normal guy from my town but now insane.