The only defender of the truthers on this forum was Libertas, all left wingers mocked them.
What does this forum have to do with anything? Majority of truthers are/were definitely left-wingers, although obviously the movement attracted some libertarian and paleo paranoids as well.
I'm pretty sure that most "truthers" would be libertarian/Ron Paul types. Not liking George W. Bush does not necessarily make one a left-winger.
I think the left wing position on the War on Terror is that it's a War for Oil. But that does not necessarily entail a 9/11 conspiracy.
There were some truthers in the left too but I don't remember any of them being elected in congress or commanding the respect of the Democratic establishment.