" maybe in the back of most peoples minds, they know that the existence of god is questionable, if not down right unbelievable"

Seems like a very logical reason, to me. I don't understand why people would have a problem discussing their religion, if they believe so strongly in it.

I've had people get up and walk away in the middle of a conversation....A conversation where I was always very polite and considerate of their views....I was simply questioning the whole God/Jesus system and explaining to them, my point of view. 2 People got highly offended for whatever reason and very rudely and abruptly walked away from me without saying anything. GG.