Christians fought against Muslims during the Crusades, Many Muslims want death for all non believers. The Catholic Church killed heretics during the Inquisition. The Nazis killed millions of Jews and then started killing Catholics. The Russians under Stalin killed anyone even remotly religious. Protestants killed other Protestants for being the wrong type of Protestant. Muslims killed Muslims for being the wrong type of Muslim. Don’t forget about Atheists (I believe that Atheism is also a religion, it is a religion of non belief.), Stalin was an Atheist and wanted to get rid of all religion.