ddt
Mafia Penguin
What you're talking about is actually Marxism-Leninism. Lenin introduced the Vanguard theory, that a highly-trained and organized communist party must lead the way and effectively organize the proletarian revolution, popular support or not. Marx never advocated that and thought that the proletarian revolution would come about spontaneously, as a consequence of the continuing immiseration.Yes, they were objectionable. Perhaps not to the same extent as Nazism, but they still violated the freedom and dignity of the individual, even in their idealized, unrealized form.
Furthermore, at this point in history one cannot assert with a straight face that Marxism merely failed to achieve its goals. In all of its incarnations, it leads to despotism and slaughter, without fail. One may excuse the ignorance of some of its original proponents, but to advocate for Marxism now is to advocate for the horrors that it actually produces.
There are very few examples of the latter. Do you think the Paris Commune of 1871 led to despotism and slaughter? (Slaughter sure, but by Thiers' troops, not by the communards).