Why don't theists debate honestly?

One of the things that strikes me with surprising frequency is the lack of straightforward intellectual honesty from theists when defending religious beliefs.
I’m not sure whether this is conscious bald-faced “lying for Jesus”, or a sub-conscious cognitive bias against any factual evidence that contradicts their worldview. However it turns up in all sorts of guises, from Muslims claiming there are no scientific errors in the Qur’an, when there demonstrably are, to theologians equivocating between common and religious definitions of “faith” in order to equate science and religion epistemologically.

The (admittedly rather trivial) thing that has brought this to my mind today was reading the foreword to Lawrence Krauss’ current book A Universe From Nothing in which he talks at length about the various definitions of ‘nothing’ from a simple vacuum, to absence of space-time, the quantum foam et al. He makes the point that no matter how physicists refine and define the concept of ‘nothing’, theologians will always insist that this is not the “nothing” from which God created the universe “declaring by fiat that ‘nothing’ is that from which only God can make something”.

This in itself is descriptive of the intellectual sand shifting that religious apologists employ, ending every infinite regress with a ‘goddidit’. But I have a more down to earth example from the same source.

Last Easter Richard Dawkins was in Australia where he debated Cardinal George Pell on the Q&A Television program. Reference was made to Krauss’ book, as Richard Dawkins had endorsed it but then the Cardinal describes it as a “con” because at the end of the book Krauss “admits that ‘nothing’ is not really ‘nothing’ so fails to deliver on the promise of its title.

Now Cardinal Pell claims to have read the book, then in the course of a live television debate dismisses it as a “con” despite the fact that at the very start the book makes clear that the definition of ‘nothing’ would never satisfy a theologian. If you watch the debate (video link here) you will see Dawkins’ eyebrows raise, although he doesn’t challenge the comment. But the point is Australia’s top ranking clergyman was prepared to lie on live T.V over an easily checkable fact in order to score a religious debating point.

When I first watched the debate I hadn’t started Krauss’ book so didn’t know if his comment was true or otherwise, and it is but only in so far as Krauss reiterates the point towards the end but nowhere does he pretend to be offering a theological ‘nothing’ which he dismisses right at the beginning. I’m not saying that atheists are immune from this, but in general when atheists debate theists they stick to facts and consistent definitions and don’t just make stuff up to win the argument. Perhaps it’s because to atheists ‘truth’, as far as it can be empirically ascertained, is important whereas to the religious protecting belief is paramount whether it is consistent with the facts or not.