Are there conspiracy theories, from which followers are a bigger problem today, than the theory being real would be?

A conspiracy theory from which believers make more real problems, or are a bigger deal, than if the theory would be true.
It can also involve things that if real or not, make no difference for today's situation, but people make a fus about anyway.
Imagine people saying that the word 'dove' was originally written douve (just a random example). Followers of the theory try to storm national archives to 'find the truth' and destroy national important books in the process.
Thats just a random crazy theoretical example, but lets be honest conspiracy theoriest can get quite crazy and logic is something most of them are missing.
Are there conspiracy theories, from which followers are a bigger problem today, than the theory being real would be?
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