Communism literally does not allow opposition of belief. I have read books where ENTIRE families have been jacked over in China because there were RUMORS that SOMEONE in the family is a rightist. Fall out of line, and you face instant persecution.
And North Korea has to imprison its residents so they won’t see the real world and only their clouded lens given to them. South Korea doesn’t do this, because their people appreciate their freedom. America doesn’t, and we have appreciated our freedom.