According to a July poll conducted by Scripps News Service, one-third of Americans think the government either carried out the 9/11 attacks or intentionally allowed them to happen in order to provide a pretext for war in the Middle East. This is at once alarming and unsurprising. Alarming, because if tens of millions of Americans really believe their government was complicit in the murder of 3,000 of their fellow citizens, they seem remarkably sanguine about this fact. By and large, life continues as before, even though tens of millions of people apparently believe they are being governed by mass murderers. Unsurprising, because the government these Americans suspect of complicity in 9/11 has acquired a justified reputation for deception: weapons of mass destruction, secret prisons, illegal wiretapping. What else are they hiding?
A Chimera....
fastvfr: It seems to most people I know that there is more consistency to many of the 'conspiracy' theories than there is to the official explaination, particularly in light of "Operation Northwoods" and the derailed/stonewalled "Official 911 Investigation".  
Problem is, the people are terrified of what it would mean if it turned out the US government DID do such a thing for financial profit and for the purpose of stripping away their rights. So they adapt coping strategies.  
A prime example of this is denial, wherein people will believe anything the administration says, regardless of how lacking in veracity it may be.  
Another coping mechanism is hiding their outrage from the people around them; after all, it was stated clearly by Bush Himself that if we aren't "For" his policies, we are "Against" his policies...and the people already know about the tortures awaiting those caught out by the warrantless wiretaps for the crime of terrorism (A.K.A not being a blind follower).  
Frightening times.