Dave, I'd be interested to hear your take on this. Do these people have serious mental issues or just really sure they know better than anyone else what they are talking about?
Behind the curveI'm not qualified to diagnose someone with mental illness, but yes....something like that. I think that otherwise smart people can compartmentalize beliefs and have them turn off normal logic or skills about one thing.
For a lot of us, that's sports -- we root for a team so we find a way to think something is fair or foul based on our biases. ...sometimes that politics, where we allow something for our own side that we'd never allow from the other. Religion is definitely one -- people believe absolutely indefensibly crazy, fantastical things that they would never allow themselves to believe about something else. And for some people, that falls into conspiracy, whether it be flat Earth, cryptozoology, chemtrails, government conspiracies, whatever.
I'm a human that is susceptible to all the same kinds of things, but I really make an effort to check myself when I support an idea and ask myself if I'd feel the same way if it was coming from an opposing position. I think I'm pretty OK at it, but it's something I've actively worked towards for decades. Whatever belief I have, I would like to believe that new facts and information would allow me to change my position.
That said, I'm just not interested in conspiracy stuff like Flat Earth because I don't think that the people who hold those beliefs are coming through reason and I don't believe that (in most cases) there is anything to gain in engaging them. In order to have a conversation about something that is meaningful, you both have to start with a shared set of facts. I don't share those with conspiracy theorists, so I find them dull. "How can we know anything?" is inherently destructive of sharing ideas.