One of the more interesting aspects of United 93, at least for me, was the lack of any black and white stereotyping in the case of protagonist vs. antagonist. While it could be argued that since each of the passengers on the planes were seen only through the glass of their final ordeals and therefore "free from sin," the same can be said of the hijackers, if only from the POV of their religious motivations. There is no undue demoninzing or hero-worship on display here, merely an account of what happened. In that way, I found this movie to be an interesting exercise in moral ambiguity. The filmmakers do not bias themselves, though I am sure all of us can understand that the hijackers are the "bad guys," and because of this all the motivations are seen as a kind of gray area.