Recently a friend and I (he's a bit of a conspiracy nut, but still able to step back and think critically, so I value him for points of view contrary to my own) were talking about what makes something a "conspiracy theory" ...which he thought meant people should just automatically not take them seriously, which was a bit unfair to someone's beliefs.
My take is that conspiracy theories generally aim to point blame (the lizard people/illuminati/puppet masters/big corporations etc. did it!!!), and are structured in a way to be interesting and sensational, in a way that makes people take an interest and want to believe, latching on to the points or connections the theory makes, and dropping the barriers of questioning those points or the underlying things that you have to accept.
There is no way even a dozen slaves could have lifted the blocks that built the pyramids, but if aliens had the technology to travel to earth, then it makes sense that they could hav helped build them!" -- slaves not being able to lift blocks seems solid to assume as true. then if you also assume the two following "ifs" are true, that aliens visited earth and that they had tractor beams or whatever, then you now have a body of logical evidence... to support what you want to believe. If you don't just assume those two "ifs" are true, then it all falls apart.
Conspiracy theories work by slight-of-handing made up truths in with real ones, which is easy to do when you lead with triggering people's excitement to want to believe or know more about something. It helps a ton if it gives them someplace to put blame about something they're not happy with.
JFK - the government is fucking things up
Moon - I dunno on this one
Samsquanch - smug scientists who can't make up their minds on evolution
rigged election - this one hits so many points of anger for people
kung-flu - I'm mad I have to wear a mask.
To the discussion on what (loosely) makes something a conspiracy theory, or rather what keeps something from falling into that category, rather than blame, they just explain. instead of every detail being intentional, they're a mix of intentional acts, and just reactions to outside circumstances. And finally why they might be interesting or make you go "huh, how bout that" they don't involve a feeling of "OMG you're not gonna believe what really happened!" In summary, the truth usually involves things outside of control, and is kinda boring.
911 - whats more likely, it was orchestrated by the government, or the government was too complicated and inept to stop it.
Never let the truth get in the way of a good story!