Carrol, I am surprised at you for being so ahistorical about this. I was going to let this pass by with Chuck but since I am one of your ardent readers on this list I can't let it pass with you.
First, I don't think that 9/11 conspiracy stories are necessarily racist. Some may be. But as a counter I would ask you to think back a few years to the first time you heard these stories. After 9/11 in NYC and NJ I only heard them from African-American acquaintances and in rap music. I don't think it didn't caught on to middle class white "left-liberals" until later on. (One of the usual tracks of cultural transmission in our culture, from Afican-Americans to white liberals.) Some of the stories, though not all, were tinged with anti-Semitism, but the latest 9/11 conspiracy stories are not. I don't think that, at origins there was a bit of anti-Arab racism.
The stories built over time. They spread along with increasing despair over ever defeating Bush or stopping the state apparatus from turning more and more to the right by "normal", electoral means. As I have said in previous posts the ones who believe these stories also tend to believe that somehow the Bush "stole" the government from "them". And this is what this conspiracy story has in common with practically all other "left-liberal" conspiracy narratives I have come across or can remember. Basically, and this is my second and main point, these narratives are left-liberal versions of "stab-in-the-back" narratives popular among right-wing and fascist movements.
The idea that there has been some sort of secret coup d'etat, and the Republic has been stolen, is a constant and continuing left-liberal "meme" (the best word in this case, though I don't abide by "mimetics") and I think if you look back, it is a constant "explanation" in U.S. history. Since the beginning of the Cold War among "left-liberals" this meme has popped up to explain the Korean War as engineered by the China Lobby, the assassination of JFK and the Vietnam War, and the "so-called" October Surprise. Actual conspiracies such as the Tonkin Gulf incident, Watergate, and Iran-Contra were overgeneralized and used to explain to the "middle class left" how our government had been taken over by a secret cabal who are responsible for every nefarious foreign subversion and invasion. Over and over these conspiracies are used as a (inevitable) substitute for class analysis, and to explain the source of the sinking feeling that things have gone so "wrong." This "left" version of a "stab-in-the-back" narrative, is potentially dangerous, but is usually only hugely diversionary. The reason they might become dangerous is that given our usual apolitical culture, these conspiracy narratives can morph into any kind of politics at all.
Confining ourselves to U.S. political history, I think a lack of a strong working class pole and a guiding class analysis, often explains why the middle class left grabs onto these narratives to explain why the world is not going according to what they learned in high school civics. There must be some explanation, and for some the conspiracy narratives fit the bill. In that way we can concentrate on "taking back" our government instead of reforming or changing the system that leads to imperialism, etc.
All of this is of course speculation. But it is speculation based on coming across the same kinds of explanations over and over again.
I might also be wrong on my diagnosis that 9/11 conspiracy narratives are not racist. Perhaps the narrative has a racist background, but surely all of the similar conspiracy explanations, that abound in U.S. political culture are not similarly tinged with racism? The point I am making is that the explanation that these narratives offer are highly "utilitarian" and are used to explain the disjunction between the "government" and the rest of us. Many of these people are pretty liberal and they have a hard time understanding why they keep losing, even when they seem to win. It must be a conspiracy!
Jerry Monaco