They don't "explain their reasoning" because they are not reasoning. When you feel vulnerable, and are at the same time ignorant, anything that makes you feel safe is going to be latched onto with real tenacity.
So the question, at least I think, becomes "what do you want?" Knowledge or security? And I think to one extent or another, we all want both. In my case, though, having never had security, I've never come to think of it as something to fuss about, but I simply adore knowledge. For many others, I am certain, knowledge that is perceived as a threat to security will be seen as so dangerous as to need to be rejected entirely.
And you know, the examples are absolutely legion. Just for the simplest, think about the family of someone who turns out to have committed some terrible crimes. We have all seen the mothers and fathers of such individuals vehemently denying...in the face of incontrovertible evidence...that it is impossible, that the evidence is made up, that this son could not possibly have...yadda yadda yadda. Because the admission of knowledge is simply out of the question.