But you don't try to make Presbyterians accountable for the few Christians who refuse blood transfusions to the point of ending up with dead children.  

Most religions have a nutbar brand or two kicking around to swell their ranks.

While I don't disagree with the idea that Islam has some particularly virulent brands that are wreaking havoc everywhere they go, I don't have any reason to imagine that mainstream Muslims are any more responsible for the conduct of Islamic militants than I am for my fellow atheist Mao Zedong.