After 9/11, a lot of ultra-leftists opined how this was a tragedy, but in the next sentence, there was the inevitable "However...", followed by a litany of reasons why America deserved, or inflicted the tragedy on, herself. It seems to me that those same people are writing negative reviews about this movie. They won't say it explicitly, but they can't allow themselves the possibility of a moving story on the subject of 9/11 to be successful in any way. Therefore, they'll declare it mawkish, exploitative, less-than-credible (forgetting about poetic license when it doesn't suit their point of view), etc. Very transparent and shameful if you ask me.