In my experience, intelligence isn't necessarily what's lacking. Strange but true. I know some very smart people who are True Believers, including my sister and my primary care physician (I'm in Kentucky, what can I say). What's lacking is that ingredient of personality or temperament, or psychological balance, that requires you to believe what science/history/Biblical scholarship demonstrates to be true (or at least highly probably, or more true than not). It's an absence of interest in being informed, and a powerful need to feel happy, comfortable, and virtuous. Anything that threatens that need gets thrown out unexamined. As they used to tell us: "God said it, I believe it, that settles it."

I have to add that I didn't encounter hypocrisy among the Baptist preachers I knew. I did encounter megalomania once. But on the whole they were nice, decent people whose minds were locked shut.