I think one of the key "motivations" behind the conspiracy theorists is Pride. They aren't smart/educated enough enough to understand how it could be done - and too proud to admit that someone else just might be smarter/more educated enough to actually understand and DO it.
By pointing out the alleged evidence of a conspiracy, they can pretend (at least to themselves) that THEY are the smart ones. Enough other stupid (yet convinced they are smart) people agree with them, which further bolsters their egos.
Some people are just too insecure to admit there are things which they don't know or understand. Therefor, they invent explanations that they can understand - and cling to a belief in those explanations. Some people can't understand the relation between mass and gravity - therefore we have a "Flat Earth Society". Some can't understand that complex lifeforms can gradually come into existence by following simple rules of evolution, and therefore we have "Intelligent Design/Creationism".
For those of you who ignored the thread about the NasaScam dude, and missed my recap of my correspondence with that nutter, I'll give an example of how they "function" (or "malfunction", IMHO). First, what ever they think is a FACT. If you disprove the "fact", or point out the contradictions, they immediately resort to anger. The NasaScam dude, on his website, said - in the same paragraph - that the shadows on the moon should be darker because there is no atmosphere to slow the light coming onto the moon and lighting up the top of the LEM, but there's no air to carry the reflected light back to the light up the underside of the LEM. When I pointed out this contradiction he immediately resorted to the kind of language I wont use on an "all ages" forum!
By the same token, the Flat-Earth people say that "down" is always the same direction no matter where you are, but can offer no explanation of why that particular direction is "down" - it just is!
