As for "how is Stalin a rightist", how isn't he? Looking at his Wikipedia bio he seems basically indistinguishable from Hitler, but he called it a different word.
No, I am falling back on the entire body of left scholarship with the exception of the French Theory school and the non-DSA New Left, who have hijacked the “left” term and refuse to acknowledge its history.
The DSA, an actually serious left-wing group, acknowledges the broad spectrum of left movements and does not attempt to gatekeep. I would say that ultras should learn from them, but ultras are part of a religion, not a political movement—they are not willing to tolerate dissent.
(Also, the poor state of modern leftism is likely a result of well-documented intelligence and law enforcement interference in left movements. Since the 1960s they have been heavily involved in promoting the “cultural” left over the economic left. This would explain the emergence of the with-us-or-against-us tendency among ultras, it’s a great tool to divide and conquer.)
As for "how is Stalin a rightist", how isn't he? Looking at his Wikipedia bio he seems basically indistinguishable from Hitler, but he called it a different word.