I actually deeply admire your post, which is nuanced in the extreme. There is not much I can disagree in a general sense. My knowledge about Marxism comes primarily through the study of European revolutions at University level and it annoys me to see stupid memes simplify complex historical factors based upon immature current day biases.

I would beg to differ on Stalin's attitude towards Trotsky that it was not focused upon his political ideology so much as Trotsky's initial popularity and his potential as a rival. Trotsky was just as powerful an intellectual figure after exile as he was in Moscow. The threat need be eliminated.

The last point I might make is that we are both talking nonsense to a large extent. What historical figures choose to borrow or steal from others in order to realise some political goal is anybody's guess. They can dip in and out of political theory at will. In this way both God and the Devil are able to quote scripture because the text contains all the justification that suits each according to their political needs.