Of course there isn't.
But as the OP says, the lack of evidence doesn't mean it won't soon be accepted that it happened (although I suspect this wasn't what they were trying to say).
The "9/11 was a US government conspiracy" (and various versions of that) makes it clear how easy it is to sell conspiracy theories, and that was only 16 years ago.
If you take the WC with a grain of salt, what prompts you to have unshakable belief that power groups inside and outside of the US Government haven't puppet-stringed it from time to time?
Have you read credible research on these subjects? Not crackpots, those are everywhere. I mean well-researched, documented, foot-noted work.
I'm just trying to find out where you're coming from so I can suggest a Reading List for you so we can intelligently discuss this. Thanks!
I'd like to point out how smug this line is, in case you haven't noticed. This kind of thing isn't useful to HN discussion, imo.