The pejorative use of the term was created by people who didn't want to be noticed conspiring.. as a means of shaming people into ignoring their crimes.
In the groundswell of public skepticism toward the Warren Commission’s findings on the assassination of President John F. Kennedy, the CIA sent a detailed directive to all of its bureaus. Titled “Countering Criticism of the Warren Commission Report,” the dispatch played a definitive role in making the “conspiracy theory” term a weapon to be wielded against almost any individual or group calling the government’s increasingly clandestine programs and activities into question.
The pejorative use of the term was created by people who didn't want to be noticed conspiring.. as a means of shaming people into ignoring their crimes.
https://projectunspeakable.com/conspiracy-theory-invention-of-cia/