As with many things, the underlying problem creating conspiracy theorists is the mediocre high school dropouts need to feel superior to others in a world that values you for your skills and education. American Psychological Association: "The researchers found that overall, people were motivated to believe in conspiracy theories by a need to understand and feel safe in their environment and a need to feel like the community they identify with is superior to others."

If you can't develop a sense of pride by working hard to create actual merit, why not just fake it by grouping together with a bunch of other flunkies to be like "actually, we're all better than you, because you're all just sheep who believe what the government tells you!"

Bonus points if you combine this line of thinking with some other forms of discrimination, but even traditionally marginalized groups can fall prey to this trap. I'm not sure how to solve it, perhaps a stronger social safety net would prevent people from losing their grip on reality just to feel safe from perceived threats. Then again to quite a few people "black people" and "women" and "people from other countries" and "trans people" are threats so perhaps nothing we do can make them feel safe enough to stop being annoying online