The clue for understand why American people don't accept the scientific evidence that point toward the hypothesis that World Trade Center's Twin Towers and Building 7 colapse was an controled demolition lies in the psychological process named "cognitive dissonance":
"Cognitive dissonance theory explains human behavior by positing that people have a bias to seek consonance between their expectations and reality. According to Festinger, people engage in a process he termed "dissonance reduction", which can be achieved in one of three ways: lowering the importance of one of the discordant factors, adding consonant elements, or changing one of the dissonant factors."
That's why, every time academics and scientifics point toward the controlled demolition theory, American people decide to ignore and deny that kind of information or label that information as "conspiracy".
But one of the important things that American people forget (or deny) is that all the scientific facts and evidence that support the controlled demolition theory were propose by experimented and talented professionals, not by people with psychological problems and Internet access.
All the scientific evidence is there. All these academics and professionals demand a new scientific investigation about September 11th terrorist attacks. That was the first global terrorist attack. That's why all the world need the truth.