Well, I said 'some', not 'all', but I think 9/11 conspiracy theory (which is the main topic, btw) is put that way.
Ok, so let's go one step back. All we see, in the 9/11 situation is that the government's story is incomplete and we have the right to suspect it's lying. Alright. You have my agreement here. Yes, we realize with some degree of confidence that the government had probably worked out the story to support their further plans. B-U-T! You won't be able to explain that the government had actually designed or performed it! Simply, because you don't have a proof. So, until you venture a proof, I think there's no point to go on blaming the government for designing the 9/11.
In my opinion, the 9/11 was designed by the other people. And not by the Al-Quaeeda and Bin Laden. I also think those who work for the FBI are not less smart than those who create those videos, and they obviously have much more facts at their disposal.
I think the FBI knows who caused 9/11, but that is not the US government. What do you think of that?