I think it should be noted, at least in terms of the evidence which may be used to support or refute a given position, is that (in most of these situations) few people are actually qualified to evaluate the evidence, and even fewer people actually have physical access to it to be able to examine it firsthand.
Take, for example, the fake moon landing conspiracy. Personally, I had nothing to do with the moon landings. I wasn't there, so I have no personal knowledge of it either way. Like most everyone else at the time, I saw them on TV and believed what I was seeing. I had no reason to believe that it was faked.
About a decade later, I heard about the conspiracy theory that the Moon landings were faked. I didn't really believe that it was faked, but I thought "well, maybe it's possible" and left in the realm of minor mystery. There wasn't anything I could personally do about it, and it didn't seem to affect my life one way or the other.
I didn't really have any personal stake in going out of my way to disprove any conspiracy theory, nor did I take offense at it, nor did I raise alarm bells about the fact that someone believes something that might not be true.
That's the other side of conspiracy theories that seems even more outlandish, when people act like the sky is falling because someone believes NASA faked the moon landings. It's not the end of the world, yet I've encountered a number of people who take great umbrage at the very idea. That's what I could never understand. Why make such a big deal over it?
I can relate.
I give you an example.
Many (in Europe and in the US) believe that aliens exist, that they have been visiting our planet, and that the US does anything to cover all this up.
Personally, I have never believed in aliens' existence.
And I couldn't care less if some people do. Or worse, they believe in a cover-up.
Because my life does not depend on this matter.
Other people do care. They want to stop you from believing in certain theories. But actually some of them are facts. Not theories.