We have had Crusades and Jihads based on religion. It seems to be the hottest button to push for war to occur. That also means that there is no civil discussion that can occur when there are so many extreme sides.
My assumption is that there are maybe 50% of ADers that would consider themselves as active Christians. The other religions take up much smaller chunks of the pie, along with Agnostics, such as myself. If the Christians think that everything will be discussed civilly, imagine a few hardcore Muslims posting that Jesus is not the Chosen One, etc. Can you imagine the ganging up that would occur, all in the name of God?
The thing is, most every religion is based on teachings that have little factual basis. It is a way of life. People choose to live different ways, based on their religious teachings, and when this gets discussed, every side thinks their side is the right side.
My reasons for my views are that I cannot trust humans to teach me what is right, because of greed. I try to be kind to others, and help those that need it. After watching all the televangelists fail because they worshipped money a bit too much, why should I pay someone else to teach me to live my life the right way? I think I do that without cost, by respecting my fellow man.