I think there's another phenomenon here that is important but hasn't been mentioned yet, and that cuts to the heart of how highly valued is a concept of truth. I suspect most HBs are people with no particular affinity for truth, but a great affinity for feeling "amazed" and "in the know". HBing is a form of "magic bullet" type thinking, where you can circumvent all the laborious effort that was done to put people on the Moon and just read one book or website that claims it was a hoax, and suddenly you are an expert. The "magic bullet" approach to knowledge is found in many places and in many guises, but at the bottom of it, I think you always find someone who loves something more than they love the truth. This is very frustrating for scientists, who tend to rank love of truth very highly, and they don't understand why others wouldn't do that also. Unfortunately, it takes all kinds to make a world, including some that can be infuriating to those who have made different choices about what matters.