I've said this before but it bears repeating. If someone tells you that you are a conspiracy theorist, ask them if they believe that Lee Harvey Oswald acted alone in the assassination of JFK. In all likelihood they will hem and haw and say, well but the Mafia...the FBI...in other words, they do not (in accordance with most people). You may then inform them that they themselves are, in fact, a conspiracy theorist. That is where the term comes from, via the FBI. Sure are a sh*t ton of us, huh?