One thing that gave me a different perspective on this is that conspiracy theorists tend to believe a whole load of conspiracy theories. And the conspiracy theories that people believe follow certain patterns: they can be falsifiable, but not so easily falsifiable you can’t come up with some arguments that take real work to debunk. And while they obviously contradict mainstream beliefs, this combination alone is not enough. Basically, someone needs to plant the idea for it to spread: most people aren’t deciding for themselves that everyone is lying about the Earth being round, they get it from someone else.

I think all this tells us that it’s not really about the facts. There’s a cognitive bias at play here which engenders belief in things which enable the believer to feel like they’re in on a secret and are therefore one above the common person.