Before the JFK assassination, 'conspiracy theory' literally meant a theory about a criminal conspiracy. In the case of the JFK assassination, all theories that were counter to the official lone-wolf theory were conspiracy theories, theories about multiple people being involved in the assassination are categorically conspiracy theories while a lone-wolf theory involves no conspiring. Due to this, the term 'conspiracy theory' shifted to mean any theory that was counter to the official narrative.

For instance, all theories about 9/11 are conspiracy theories in the literal sense. Even in the official 9/11 Commission Report theory, a bunch of men conspired to hijack airplanes on the same day and crash them into buildings. That's literally a theory about a conspiracy. But in the new meaning, this is not a conspiracy theory because it's the government's officially endorsed theory.

Whether the CIA induced this verbal judo deliberately is another question. I'm inclined to think they didn't. I think it was a natural language shift, albeit one that has been harmful to society.