I agree that such mockery isn't very charitable, but there is an underlying line logic to their thinking. We know that a system like North Korea's is possible. We know a system like ours is possible. We don't have any evidence that any other system is actually possible.

Sure you could imagine something better. But such a system could very easily have fatal flaws you didn't imagine. In fact, North Korea started as just such a utopian ideal.

You could also argue that we used to have a system that was better than this. But if that system ultimately became this one, than reverting to the previous state would likely at some point result in the current state occurring again.

So in a sense "Do you want to live in North Korea?" is the only valid question.