I just watched Loose Change, a documentary about how the 9/11 attacks were actually arranged by the government. It's poses a lot of really good questions, but the narrator is annoying and much too blatantly one-sided. The movie doesn't just pose questions and give the possible explanations (and likelihood of those explanations.) The movie flat out says that we are being lied to and that it was the government that did everything; so, all of the potential for good that this movie could wield is removed. The movie isn't going to cause any wide-spread popularity, or revolution starting because it doesn't allow the audience to think for themselves. It tells you what you should think and that breaks rule number one of any documentary/news story. The best thing to do is present the case and let the audience decide. If you tell people what to think, they will be turned off and likely ignore the message of the film.

Maybe I'm just digging around in my film making training, but that's what I think.