Except there are extant, positive examples of liberal states.
Every time people have tried to set up a communist nation, it's turned into an authoritarian shithole at best. And when those countries moved away from communism they became less oppressive.
As ever this topic just invites the laziest sort of induction from lay people. Something not having happened yet doesn't preclude it from happening.
Additionally this totally ignores the context of the rise of communist regimes in general, and what that means inside Marxism in particular. The revolution isn't supposed to happen in backwaters like Russia, or any of the other places you claim it's turned into an authoritarian shithole (as if they weren't previously).
It's just a bad argument, made worse by vapid appeals to being a historical argument that magically somehow avoids actual history in the form of context.
Are you really comparing capitalism to communism?You obviously don't know what you're talking about.
Of course, people always compare them. And you might find I do know quite a bit about what I'm talking about.
Handwaving away the things Capitalism has done isn't the answer to giving you a good argument.
Though I find it funny that I've never once gotten anyone on this site to actually give some sort of answer to
An Gorta Mor. People use horrible things that happened under Communism as if it's a trump card, but when they happen to Irish people (under high classical economics no less) they are totally fine.
It only works on a very small scale. It does not scale because people like individuality and are generally self interested.
The thing that bogs down these topics is that no one's read Marx. Marx's argument, right or wrong, is that self interest will drive the revolution. You can't just say self-interest and walk off, Marx is a Smithian and Materialist. He thinks self-interest is driving everything.
Some sort of specific articulation about self interest is necessary to make an actual argument.