Great post, cofty. I think that you are laying out many interesting points about morality and believing in a deity. What find I interesting is that the same exclusive association with morals and a "God" adds to the challenge of making believers value what we atheists contribute, considering that since the very first moment we're seen as amoral people, non-believers, etc., and therefore, we are perceived as all kinds of things except, well, right.
Adding to the difficulty of some people holding on to their believes and trying to make their deity be perfect is the fact that many believers have made many important life decisions based on such set of morals, based on those believes. Their investment is high. Furthermore, they fear losing the only thing that they believe is the only source of happiness, structure, education, and community.
It was great reading your post.