If an atheist brings up the Christian Crusades is best to know the actual history of the Crusades. The Crusades were the Muslims attempt to conquer all the land that existed around them by trying to mass murder anyone they could find. The reason is called the Christian Crusades is because the Muslims wanted to smear the Christians and of course the atheists had no problem with this. So they agreed with this lie and pushed it as truth. When the Christians fought the Muslims they were defending the people and their territories. As shown in the map below.