The problem I see with all these types of films...is more often than not emotion takes over from fact too easily.
The WTC incident is a part of pop-culture now, like Goon said, alongside the Holocaust, sensitive and upsetting subjects, open to interpretation and fodder for documentary makers. But when films go into patriotic/upsetting mode, most stuff gets thrown to the side to be replaced with a repeated story.
I think the film isn't too close to the events taste wise, it's just too close to make these films completely unbiased.
Damn that sounds cold, but eh...lizards.
EDIT: Oh, especially with tossers like Michael Moore playing the fool and changing facts for his own perverse uses. Read his books, seen his films, can see through him like an opaque silhouette. He's like a Goebells for the 21st century.