Well, I disagree. Hindsight may make blame irrelevant or unfair for the reasons you list (although I wouldn't go that far), but it definitely doesn't mean we can't use our position in the aftermath to discern the truth. And since our politicians' foreign policy has often been used not only to react to international events but also (even primarily sometimes) as a domestic power play... it does not seem farfetched. Speaking of, nothing has changed. Don't forget Africa. The thing is, there's just not a whole lot of evidence (being nice, here) that the communist grassroots movements in any of those places had anything concrete to do with the mother country. In many places they existed as local factions. There's even some evidence that by drawing the Soviets' attention to those localities, we merely encouraged them to foment whatever anti-American/nationalist/populist ideology they noticed lying around. Arguing counterfactuals never gets anywhere, though. Not sure what really happened. I just don't think it unlikely that we exaggerated the threat. If we did so out of fear (as some assuredly did), that's excusable. But if we also did so to cement power selfishly (as I would heavily bet was the case -- hell, remember Kissinger and Vietnam), whole different animal.The historical camp is irrelevant, as that has the benefit of hindsight.
This may not in itself be a justification for our nonsense in Latin America and Southeast Asia, but in my opinion it's a bit unfair to call communism overblown. The world could have been a much better place in the 20th had Stalin not taken over Eastern Europe (to say nothing of Mao's nastiness, but of course China wasn't really a security threat to us at that time).