Things are terribly oversimplified about these topics.
The US history is hugely distorted - we've destroyed more democracies and created more dictatorships than the other way around.
The history of communism is broadly misunderstood - for example, was there any chance that an authoritarian system of some sort wasn't going to take hold in China? Chiang Kai-Shek's government was quite bad and there's a reason he was opposed.
A lot of smaller communist countries have had far more powerful countries attack them economically, making their problems much worse.
The issues are quite misrepresented. Interesting anecdote - one of the last communist societies overthrown was Yugoslavia. I had a man install my water heater who was an immigrant who had lived in communist Yugoslavia. He said it was a paradise, that the people there cared for each other and were very happy. Not what I'd call typical for communist countries - but when have you ever heard that side of the history?