“The “Then what” has been amply demonstrated by communist regimes in the 20th century.”
Do you mean that “they” are true believers in Communism and want to establish it as widely as possible for the good of humanity so that everyone can live happily ever after?
Oh, yes.
That is exactly what I am saying.
Of course, if you ask them right out if they are Communists or Marxists, or even Socialists, 99.9 % of them will deny it with a straight face, and will do so right to your face without even a twitch or a blink.
But if you look at who they are, what they do, and what they stand for, they are.