They are doing exactly what they have been brainwashed to do by their religious leaders...
There are several branches of Islam. Some are more militant and some are more liberal. However, when you get down to the core of their main purpose for existence, it is to eliminate the infidel. This is a racist effort just as Hitler endeavored to cause genocide on the Jewish people. The Muslim religion is being used to further a racist purpose. A bank robber is one who steals from a bank and will kill innocent people if necessary. He will use hostages to further his plan. The Muslim wants to steal land, kill innocent people and and uses religion to further his racist world view. I think this describes a killer machine.