The thing about conspiracy theories is that when people who hold power over large groups of people actively mislead them and deny them of a source of authority,

The thing about conspiracy theories is that when people who hold power over large groups of people actively mislead them and deny them of a source of authority, those people grasp at what pieces of information they do have in order to build a narrative that isn't tainted by lies. It is, and I cannot stress this enough, entirely unhelpful for you to ascribe it to main character syndrome or compare it to the belief in an omnipotent God. If sources of truth in human societies like governments and scientific institutions would stop lying or misleading people nearly constantly then you could call conspiracy people lunatics, or fringe. But you simply cannot. Not only are people being lied to, but they are being actively disinformed for "their own good." There are massive socializing forces that have taken an active role in manipulating society based around the idea that they know better. And the ironic part is that, to a degree, they do know better. People act stupid in groups and have important information WITHHELD for various reasons that make it impossible to discern the truth. If you want to start minimizing the amount of bullshit beliefs that people hold, supernatural or otherwise, you can start by tearing down the systems that are used to create false narratives which push people into those beliefs.