The guy who answered you is actually right.

Outright military interventions and coups are part of the package called the real world.

Anyway, I would replace "capitalist" with "bandit" here. Because "capitalism" is just as square-abstract as "communism", while IRL just as vulnerable to those.

See, there's an important thing called "feedback". If there's no feedback from you, your life doesn't matter and you get stomped upon.

60s-70s USSR had very weak feedback mechanisms, but still surprisingly better than today's Russia. Some things that people just accept today would cause real protests there. Half the ministries would be paralyzed by people saying that following such a policy is against their conscience. I really believe that, yes.

But then, due to its slow collapse and decay, those feedbacks becoming stronger started pushing for change that would deprive the ruling class - KGB and similar or related people, bureaucrats and relatives, anyway, the real structures usually don't have names, - of power. That's when that class hijacked the popular movement from the likes of Sakharov or Starovoitova and created modern post-Soviet states.

Which means that it had blind zones with no feedbacks said class used. And the more centralist-bureaucratic and non-transparent a state is, the more blind zones it has.

Anything that takes the power from being distributed between separate people and assembles it into one Moloch, calling it "power of the people", controlled by hell knows whom, means that those people who actually have principles will get stomped.

As we can see, though, same things happen in countries very far from being "communist" or "socialist".