A great point about the fundamentalist 'bunker mentality', the habit of hunkering down defensively inside their insular group and labeling everything that is 'other' or 'outsider' as a threat, and intellectual pursuit doubly so. They want a bubble, a way to surround their subculture and insulate it entirely from 'the world', the outside, those that are different from them.
I grew up in that bubble, and when I broke free of it, I felt like Rapunzel leaving her tower. I grew up so isolated from everything that did not agree exactly with my parents beliefs, that it was the same to me as if I had grown up in a tower, cut off from everything around me and unable to explore or learn or grow in spirit. That is what this mentality ultimately does, in fact wants to do, to it's children.
A stone prison with no key, no way out, no help and no hope. No life. This faith is barren.