If someone is earnestly posting incorrect information, you should reply with a counter-argument, or upvote one that exists. Otherwise what you're doing is the exact opposite of being conductive to a dialogue, which is the entire point of the hacker news comment section. Sure, downvote people who are being disingenuous, or not being honest.

Also:

> Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.

So far, everyone has responded to my talking about Cuba, an example I picked off the top of my head as a simple demonstration (It's a shame that America cannot boast such scores in education and health, to be honest). The example was illustrative, something mentioned off-hand to solidify and strengthen a point. Nobody responded to the core of my argument, which was the more meatier part and harder to disagree with.

My central point, however "An economy cannot work without foreign trade, being blocked from that by a major player essentially does that" is supported by economists literally everywhere. In fact, it's one of the major reasons why a trade embargo is created in the first place, to suffocate a country and cause a regime change:

     "By far, regime change is the most frequent foreign 
     policy objective of economic sanctions, accounting for 
     80 out of the 204 observations."
     - Economic Sanctions Reconsidered (3 ed.) -- Hufbauer, Schott, Elliott, Oegg

what erroneous information is he providing? That communism isn't necessarily destined to fail?

That's a matter of opinion.

I don't support cuba or leninism, but I just don't see anything controversial with what the parent has said, whether you are left or right wing.