I agree - it does seem like an awfully limiting worldview. I think for them it seems safer - the world maybe doesn't seem quite so big and scary if they think "oh, it's all understandable, we just haven't figured it out yet but we will." It reduces the world to something that they can tell themselves is controllable, predictable, and otherwise within the scope of human comprehension. I think it's the opposite extreme from the Born-Again Christians' tendency to think the Bible = God, and if it isn't in the Bible it's A)heresy or B)unimportant.