communism has historically relied on iron-fist dictatorship

I don't think that necessarily follows (you seem to be equating Stalinism and Maoism with Communism):

to try to say that most or all communist dictatorships are only dictatorships because of foreign intervention (what you seem to be saying) is a real stretch

That's not quite what I'm saying. What I'm saying is that many to most to all of the governments that were approaching communism had their minds changed by the Western world. I don't think that there has been any country that has peacefully become communist, despite the fact that there have been any number of democratically elected communist governments that have mysteriously been followed by nationalist coups. The only countries that are communist now are so because of rebellion, not popular choice (despite the fact that those rebellions were largely popular, at least at the time).

This could mean that it doesn't happen. It could also mean that it's never been allowed to. It's kinda like saying that a vending machine doesn't accept nickels based on the fact that every time you put a nickel in it, you hit the coin return button, and you get no product.

apples ... kumquats

Good point.