So I get the proxy war aspect, but to the extent people in the US govt believed that communism was an evil form of govt and that for any people to live under it was hell, would you call them disinterested? I think this is the point Buckley is driving at.
Chomsky's response was that that is all theoretical and not real world stuff is well taken, but I'm not sure why he can't concede the point, and then say that the problem is we, as the US, have this general, simplistic notion and don't do enough on-the-ground intel to figure out if we are right or not, as you and Crazy seem to be pointing out. I think that same idea applies to Afghanstan and Iraq, as well.
Discovering what is in a nation's best interest is amazingly complex and context driven, and is best left to those who live there and will suffer the consequences. Unless we are going to devote a lot of time, effort, and research into a nation, it's people, the various sides, etc., going in with some general theory of the good to advance probably is going to end in disaster in cases where there is a legitimate internal struggle over the form of government.