Religion is not the cause for exrtremism. But the people belongs to one religion always been on the receiving end and when they reacts against the aggression/attrocities, the blame goes on the religion. It is the media propaganda to project all extremism on a particular religion. When a muslim involved in even a personal argument, that will be highlighted as "Muslim fight", while the other religious people even kill someone, that will be notified as "a person killed his neighbour". That is the way Media brings the news to public. So extremism is the creation of media and master minds behind those dynasties.