I don't think that makes sense - they only bombed a small percentage of Cambodia but no doubt the turmoil helped Pol Pot get into power.
"...it would be a credulous fool who swallowed the (unsupported) word of Osama Bin Laden that his group was the one responsible. An attempt to kidnap or murder an ex-president of the United States (and presumably, by extension, the sitting one) would be as legally justified as the hit on Abbottabad. And America is an incarnation of the Third Reich that doesn’t even conceal its genocidal methods and aspirations. This is the sum total of what has been learned, by the guru of the left, in the last decade."
https://slate.com/news-and-politics/2011/05/noam-chomsky-on-...
Also, of course Osama Bin Laden did 9/11. The part that doesn't get talked about is that we blatantly antagonized this sort of result by (by in part the funding of) murdering and dehumanizing people worldwide in the name of ideological and economic dominance and called it progress.
Chomsky's foreign policy views can somewhat accurately be reduced to "everything is either American imperialism or reactions against it," to a degree that he ignores the imperialist tendencies (and other unpleasantries) of countries that aren't the US because they're against the US. For example, his denial of the Cambodian genocide essentially boiled down to "well, the US doesn't like the Khmer Rouge, so therefore everybody criticizing the Khmer Rouge was overselling the criticism, how was anyone at the time to know what they were doing?"