In all honesty, I'm not especially keen to argue about theism/ atheism either. I'll expand my original point and hopefully that will make the purpose of my last post clearer.
People like to have consistent cognitions (ideas, beliefs etc). Sometimes, however, stuff happens and they find themselves in the position of believing contradictory things- in the psychological literature this is called cognitive dissonance. One example of cognitive dissonance might be this:
Joe considers himself to be an excellent driver. But then one day he doesn't pay attention, and he causes an accident, injuring a pedestrian. He is now in a position of cognitive dissonance- he thinks that he's a good driver, but he also knows thats he's injured someone through poor driving. The two are contradictory.
Okay...so there are a number of ways through which people can eliminate the dissonance. For example, one way for Joe to resolve things would be to decide that the accident wasn't his fault- then he could carry on thinking that he was a good driver. Another would be to revise his opinion of his own driving. A third might be to tell himself that all good drivers occasionally make mistakes, and he was unlucky. And so on.
However, the most effective way of dealing with cognitive dissonance is simply to avoid getting into the dissonant situation to begin with. Avoid inconvenient facts. Don't examine your beliefs too rigorously. Don't think about the logical consequences of your worldview. And it is this tactic that I think is adopted by many Christians. If they did take a long hard look at what they believe in, then they'd find plenty of contradictions. For example, the Loving God/ Torturer God contradiction that I describe above.
Thus the survey findings. Christians are avoiding knowledge of their religion as a way of preserving their beliefs. Greater knowledge would bring with it the threat of cognitive dissonance, which is something that people generally wish to avoid.