A conspiracy theory is an attribution theory: it asserts (by its nature) that some observable phenomena is attributable to the intentions of some group, and creates a structure/system in which that group has the motive, means, and opportunity to create the given (observable) outcome. Thus someone like Marjorie Taylor Greene might consider the increase in California wildfires, but instead of attributing those fires to uncontrolled forces (natural or man-made), she attributes them to some intentional action by a human agent: in her case, George Soros, trying to develop some space-based solar power system backed by money from a Jewish cabal, which has gone horribly wrong.
The heart of a conspiracy theory is the idea that bad things only happen because of bad actors, and that one must ferret out the bad actors responsible for those bad things at all costs. Thus conspiracy theorists seek out conspiracies — groups of bad actors coordinating to hide their bad actions from others — because the idea that a bad outcome is due to anything other than human intervention is pragmatically unthinkable. This is actually quite normal in a way, because people tend to think in term of narratives. We prefer stories about agents, about people who make decisions that have impact on their own lives and the lives of others; we reject stories in which unpredictable events occur for no reason. And so (to be topical) we might see someone prefer to believe a story of wide-spear voter fraud, however improbable, because the alternative is that one's preferred candidate lost where he should have won, for no readily apparent reason.
Losing is bad, therefore someone must have done it to us, because bad things don't happen otherwise.
There is no cure for conspiracy theory except the re-invocation of common sense. At some point, one has to be able to say:
Ok, this is ridiculous; something I don't like happened and nobody did it. Time
to move on.
But there will always be people who refuse to move on, and refuse to grasp that basic acceptance of reality. One has to be able to distinguish ardent belief as a thing in itself, but something that it is not an acceptable replacement for truth. Otherwise one is vulnerable to every huckster with a tale to tell.