There is a fairly simple diagnostic test for delusion: before starting any debate, just ask: "What kind of evidence would cause you to change your mind?" If the answer is 'none' then you've caught one of the deluded. Go on with the debate by all means, but treat it as a spectator sport rather than an attempt to convince your opponent.
I think that this a fair test that everyone should take before asking anyone else to change their mind on any subject. It seems like to me Jeremy does not think that the point of the debate is not to attempt to convince the opposes person(s) to change their minds and agree with them. If I understand what he said, then I must ask what is the purpose of debate and discussion between people who hold opposing opinions if not to convince the opposition to change their mind? I would actually say that convincing others to change their minds is only part of the goal of a debate. The other part is improving your own argument by seeing where it's weak or abandoning them altogether if they are not up to snuff. Grant it, this only works if both sides consider the question Jeremy asks. I find it amazing that many atheists seem to think that no one can consider and scrutinize their religion and honestly come up with the opposite answer they do. And when I follow their logic and thought processes I find so many ways that their arguments fail I am amazed that they can't see it. Truth is it should not be a surprise, the Bible clearly explains why.
Additionally, John Loftus has been very clear in his purpose: To discredit Christianity and inspire Evangelicals to leave their religions and become atheists like himself. How can he argue that he is open-minded and willing to argue as a "spectator"?
Debunking Christianity: Quote of the Day, by Jon Jeremy