Oh, it's advocated by the left, alright (damn you language), but e.g. Stalinism was much less that and much more feudalism than Westerners commonly assume; it was quite the underground struggle, and Stalin himself (even without supposing any conspiracy) fell to it, as everyone around was either genuinely too afraid of disrupting him the morning he had his heart attack/whatever it was, or consciously decided to abandon him.

My point is, if you scratch a Stalinist you're likely to find a barbarian; those smart, brave and virtuous alt-right-wingers strike me as the only sort of people who could potentially succeed in truly implementing such a regime.