In the UK an MI5 employee thinks that the planes flown into the WTC were really missiles....we all saw planes because they were shrouded by holograms....
....yeah...holograms.
OMG, WTF?
I think all the conspiracy theories are not so much about what "really" happened, I think they take a pulse on what people think about government in general. Many people, especially in the US just don't trust government, from any party.
I think government is inefficient, incompetent, spend happy group of people, but I also believe that government is absolutely necessary for our survival and I have serious doubts as to the validity of any conspiracy theory, government is just not that competent