Free speech is a poor example unless we’re talking about the DPRK

Why? Even Cuba places restrictions on internet, print, public discussion etc.

There is a respect in which socialism is more fragile. Having a distinct goal (i.e. communism), it is capable of failure. A liberal society doesn’t really have a goal other than its own survival.

I don't buy this "we are so fragile, we need to repress OUR OWN people to do a communism" bit. I don't buy it at all. The main reason for repression is the massive contradiction between the alleged goal (communism) and the actual practice (exploitation and alienation).

That aside, the issue isn’t fragility so much as the enemy being so powerful (e.g. the wealthiest country in the history of the planet) that leaving small cracks to be exploited can still be extremely hazardous.

They are right next to the actual most powerful country in the world that actively supports them. They have nuclear bombs. They have artillery aimed at South Korea, that can destroy half the country's infrastructure. North Korea is not under existential military threat. They are far more secure than Cuba so their repression is much less justifiable.

I'm not going to stan countries just because they call themselves communist. Third world countries are known for having corrupt governments that exploit their people. This doesnt magically become not true if such countries reorganize their economies to be state owned, while still maintaining the basic capitalist mode of production.

The dictatorship of the proletariat (which is not a dictatorship in our colloquial understanding of the word, but actually means mob-rule or tyranny of the majority), serves to repress the bourgeoisie, NOT the people themselves.