The Nazis as well as the Russians are of a Christian tradition. I would not say that they are good Christians, but then, Al Qaeda and Isis are not good Muslims, either.
Just because someone hollers Allah Akbar! when they score a hit does not mean that they even think they are fighting for Allah. The war with the Muslims is about the cultural control of Muslim society that is being pushed aside by Western consumerism.They feel threatened by changes in the ways leaders are selected, feminism, a lack of employment and the inferiority both economic and technological of their societies to Western society.