Conspiracy nutters are everywhere these days. George Bush and Dick Cheney ordered the "controlled demolition" of the Twin Towers. The Duke of Edinburgh, a 12th-level Mason, ordered MI6 to kill Di and Dodi, to prevent the British Royal Family including a Muslim. MI5 America faked the moon landing!
The problem with all these conspiracies is they forget how useless we humans are at running large-scale projects without fucking it up. We're just not good enough at enormous projects, particularly when they're supposed to be big secrets.
Charlie Brooker has a good look at them.
It's hard enough to successfully operate a video shop with a staff of three, for Christ's sake, let alone slaughter thousands and convince the world someone else was to blame.
PS: If you read the version in this week's Guardian Weekly, you might want to read this version. The GW version was quite savagely cut down.