Show me Christians alive today overseas who believe that mass murder and mass sexual assaults in the name of Jesus are called for, encouraged and acceptable and I'll support blocking them, too. Please don't drag some figure from the year 1272 AD, or something, into the picture to imply that "Christians commit mass murder in the name of Jesus". Such people are not alive today and are irrelevant. 

As vile as Bill Maher can be, he does have a terrific understanding of the nature of Islam and an exact understanding of the ushy-squisy "liberals" who foolishly believe that there's no connection between Islam and Islamic terror and the nonsense that Christianity and Christians "do it, too".