Even Marx’s professed goal was the eventual end of the state. He just believed a worker’s collective would be the finest expression of inter-personal liberty and perhaps egalitarianism. As a result, I agree with you that communists can of course be libertarians, and I also agree that I wouldn’t want to be part of that commune (though I could easily respect its right to exist). One unique quirk of traditional Marxist doctrine that becomes - in my mind - a pit-fall is that the transition to communism necessitates socialism and the collectivization of all capital on the road to communism. That is, on the path to anarchy you essentially need more government. I can’t say I have read every anarcho-capitalist philosopher ever (how could I), but I have never heard an an-cap argument wherein the state needed to be maximized before being shed away like a chrysalis from a caterpillar.