When hasn't it been mainstream? It sure qualified as mainstream for JFK assassinations and arguably Roswell as well. And that is before going to the Know-Nothings and their anti-catholic conspiracy theories.
Conspiracy theories about JFK, Roswell, moon-landings, and things like that are basically harmless. Well, mostly harmless anyway. Usually spread by someone trying to flog some nonsense book, or a confused "true believer".
But this is different: it's just a plain ordinary self-serving lie. Completely invented by a sad narcissistic liar and his merry band of sycophantic enablers to win ("win") an election.
There's also a type of maliciousness to it that's lacking in more traditional conspiracy theories.
We probably shouldn't even call it "conspiracy theory".
