The way I remember it was that Chomsky said a silent genocide was coming and that the US wanted it to happen. If the US had wanted one you think it would have occurred. The point remains that Chomsky was wrong in his analysis.
http://www.theatlantic.com/issues/2001/12/hitchens.htm
Hitchens put it's best:
"Having paged through the combined reactions of Sontag, Noam Chomsky, and many others, I am put very much in mind of something from the opening of Marx's The Eighteenth Brumaire of Louis Bonaparte. It's not the sentence about the historical relation between tragedy and farce. It's the observation that when people are learning a new language, they habitually translate it back into the one they already know. This work of self-reassurance and of hectic, hasty assimilation to the familiar is most marked in the case of Chomsky, whose prose now manifests that symptom first captured in, I recall, words by Dr. Charcot—"le beau calme de l'hysterique." For Chomsky, everything these days is a "truism"; for him it verges on the platitudinous to be obliged to state, once again for those who may have missed it, that the September 11 crime is a mere bagatelle when set beside the offenses of the Empire. From this it's not a very big step to the conclusion that we must change the subject, and change it at once, to Palestine or East Timor or Angola or Iraq. All radical polemic may now proceed as it did before the rude interruption. "Nothing new," as the spin doctors have taught us to say. There's a distinct similarity between this world view and that of the religious dogmatists who regard September 11 in the light of a divine judgment on a sinful society...."
Peter