Correction. They start as atheist vs theist. The theist is quickly devoured and the atheists and agnostics turn on one another in a philosophical debate about debating and words that by their very nature a varied and founded in a theological world.
The problem is the word GOD. As soon as it is used, a huge leap is made, this is undeniable. Atheist say they don't know and don't believe because historically the role filled by "God" known or unknown, has been explained away through knowledge, and this is likely to continue on. The that word in of itself if inflammatory and should have no place. If you don't say god no one has to say atheist.
Quite humorous summary