Not PC has a theory on why conspiracy theories are so attractive.
Both conspiracy “theories” and real theories purport to explain things, says Lester, but the chief difference psychologically between them — given that the chief difference in reality is that conspiracy theories are patent nonsense — is that “real theories mean work. It takes work to understand them. They are abstract, difficult.
I feel a post of my own on the topic coming up…
My own view would be that people have let their hatred of the Bush administration get in the way.
Something should go here, maybe later. 
Google has a new tool that links various conspiracy theories through related documents. It’s in beta but it’s pretty cool. Have you seen it? googleconspiracytheory.com