It's because they depend totally on a dataset containing nothing but corroborative anecdotes. Anything that goes against the data has to be rejected, for fear of undermining the whole thing. I've spoken before about the dream I once purported to have, in which "God" told me "he" doesn’t exist; and how the theist I with whom I was in conversation decided that, of the three possible options (just a dream, genuine god communion, the devil tricking me) the most plausible was the third one.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'
