Answer:
Answerer A: I disagree wholeheartedly. Some of the best inter-faith dialog occurred during the Crusades, particularly the First and Third. The House of Wisdom in Baghdad, the literary works and translations in Spain, the mutual respect and admiration of Saladin and Richard Lionheart for one another -- all occurred during one of the most infamous "religious wars". One cannot have a "holy war"; it preaches against the very things either religion stands for. I happen to be located in the U.S. and thus my focus is on the major monotheistic religions: Judaism, Christianity and Islam. Currently, Turkey is at the forefront of major inter-faith dialog break-throughs and the Second Vatican Council asserted the Holy Spirit could be felt in Islam.
Answerer B: Religions are a set of beliefs. The thing is, if you believe in a religion, you think your religion, and only your religion is the only one that's real. You can't be Christian, but think that Islam is a real religion. You just can't believe that. Maybe you can respect it, but really no one does. So people get angry and kill each other which usually causes tension bewtween religions and causes disgust among the communities of opposing groups. Then war arises, and that my friend, is why religion causes war.
Answerer A: One could argue it's not religion that causes war but humans interpreting it out of context and thus using it to justify their actions.