I think in many cases the conspiracists revel in thinking they KNOW something few others, have discovered. They are "in the know" and the rest of us peons are deluded by "mass media" and the guvmint.
Most make little sense to me, and very few would alter my life in any way if I KNEW the real truth of it. If the CIA assassinated JFK and not Oswald, well, OK, nice story, doesn't really change much. If the Earth is flat, well, that would be interesting of course. If there really are "chemtrails" and not "contrails", well, OK with me I guess. Why is someone spending a vast sum on them?