What do they think is to be gained by doing these things?
Sorry, an old quote I know, but I'd like to answer. Despite the distorted (understatement?) views of extremists (who in my mind obviously represent very little of "their" religion), it's satisfying to know (or maybe believe all by my lonesome) that the only thing they gain is a seat at the perpetual dinner table in the foulest corner of hell having all-you-can-eat dogshit with the likes of Hitler, Pol Pot, Hussein, rapists, Stalin, Jim Jones, the soon-to-be late bin Laden, etc. etc. etc.