I’d add Leon Trostsky to the List of Notable Russian Madmen. Totally amoral, slavishly devoted to the idea of “revolution,” whatever that was, and remorseless in his pursuit of it, I suspect as an end in itself rather than a means toward anything.
I think of the “revolution idea” as a mad urge to turn the world on its head to bring it into conformance with oneself, because one feels “off” in the first place.
The only good thing Stalin ever did was to kill Trotsky.