My favourite example of this is the conspiracy theory around the 80s film ‘Shazam’, starring the comedian Sinbad. (Not related to the 2019 film of the same name.)
In the early days of the internet, when people used to talk on message boards for the sheer novelty of talking to people around the world, it became a popular topic - basically ‘OMG I loved that movie when I was a kid; how come it’s never on TV anymore? You can’t even find it on VHS’. Then DVDs became mainstream and people started asking why it wasn’t being released on DVD.
Eventually it became a very big thing and Sinbad gets to hear about it. He says, ‘Sorry everyone - the movie you think you remember doesn’t exist. You’re thinking of ‘Kazaam’, which is from the early 90s and actually stars Shaquielle O’Neal [who looks a bit like him]. I never made a movie called ‘Shazam’’.
If you look up Kazaam, it has the exact plot described for Shazam - kindly, comical genie helps two orphans. You’d think this would be the end of utter. Ohhhh no. Cue thousands of people telling Sinbad he’s wrong; why is he lying?! Why can’t we watch the movie we love?!? He MUST have had it suppressed somehow.
To put this into context, Sinbad was last in the news for an unpaid $1m tax bill. He’s not influential enough to suppress THAT - but he’s managed to have a film taken out of circulation worldwide?
Google it - it’s fascinating how people are so desperate to prove they’re right, even when all the evidence screams otherwise.