Well, there is a bit of difference in believing that in an ideal world, Communism would be the way to go, and actually thinking it should be attempted at the current stage (Which frankly is a terrible idea).
That being said, there is a fair amount of irony in blaming death on Communism, if you consider that you'd be hard pressed to find a country that "attempted communism" and wasn't historically shitty to begin with. Like they could have implemented anything to replace the Tzar with, or kept the Tzardom in, and it would have been just as fucked up due to where Russia was at the time culturally and economically, and this goes for most communist countries.
Hell, most "Communist" countries specifically go for Communism because they're in such a shitty place to begin with that they're willing to follow anyone who preaches equality and fairness even if he's just force feeding them bullshit.
Also, calling bullshit on the entire concept because a country or a group of countries fucks it up to such a massive degree that it's a true spectacle to watch, would also disqualify Democracy, as you could just point to shit like the French Revolution which managed to fuck Democracy up so much that they straight up worshipped Napoleon for his great leadership after he wiped away the pathetic mess that was left in the Revolution's aftermath.
Again, it's not something that should be done with where humanity is, and probably there will never be a time where we can go full Starfleet and do anything close to it, but it's neat the same way Utopia was when Thomas Moore wrote it in Henry the VIII's court. Utterly unachievable, but neat.