What happens if the conspiracy theorist is someone you agree with? Do we still avoid mainstreaming them?
Humans conspire _all the time_; the whole of human history is marked by innumerable conspiracies between humans to achieve shared goals.
Believing that it's possible for humans to conspire isn't wrong, it's rational.
Making claims without having evidence for it, believing that shadowy cabals of people are somehow running the world or entire organisations (actually pretty much impossible in modern times), adopting scientific language but actually not understanding how science works (anti-vaxxers, 9/11 truthers, flat earthers etc..), making extraordinary claims or rationalisations without having an extraordinary good reason to make them, generally being paranoid and framing everything as some sort of power play, believing that everyone who disagrees with them is part of some establishment or has a hidden agenda, and so on.
>Believing that it's possible for humans to conspire isn't wrong, it's rational
Conspiracy theorists don't just believe that it's possible for humans to conspire, they believe that humans conspire all the time and use it as an explanation for claims that don't hold any water. Virtually 99.9% of conspiracy theories are wrong even if one or two happen to be right by accident, so it's useless as a way of approaching the world.
What about all those conspiracies that turn out to be true? Libor rate fixing, US tapping merkel, certain groups in media conspiring with certain political party, etc? Every war we've been involved in the last few decades have been conspiracies. Or did you forget about yellowcake?
Extreme paranoid thinking is detrimental but so is extreme naivety. Categorically rejecting conspiracy theories is as ridiculous as categorically accepting official narrative.
So do you accept everything Trump says as gospel? Should we shut down CNN/MSNBC/etc since they peddled conspiracies about Putin owning Trump?
For someone who rejects paranoia, you seem quite paranoid about conspiracies...