Someone recently reminded me of this essay I did. I kept seeing articles on Schneier's blog and other places talking like conspiracy was a made up concept that required nutballs to believe. Yet, there are provably conspiracies everywhere. By the numbers, conspiring against each other is one of the most common and pervasive things people do. Being that pervasive, it should be a default possibility to investigate as a cause of anything.
The problem kicks in when people aren't checking sources, aren't looking for counterpoints, being selective about presentation, and so on. More a mis- and dis-information problem than conspiracy theory itself being bullshit.