Why is religion sometimes not the cause of war?

3 answers

Sometimes it is not. Did the Spanish American War, or the Mexican War, or the WWI have much to do with religion?
Even the Crusades, the Palestinian-Israeli conflict, and the Six-Days' War were not about the religion. They were caused by the perceived needs for land, power, and resources.
WHy would it have to be about religion? SOmetimes it was, which was not good representation of either religious party, but it shouldn't be and it isn't always the cause