I could say that the fact that Sweezy pretended that he had been enlightened on matters of technical economics by reading that notable work of J.V. Stalin, _Economic Problems of Socialism_ is a historical fact.
--- You could say it, but it wouldn't mean squat. Sweezy used Stalin's writings on economics for inspiration. Big fucking deal. The USSR under Stalin had 300% GDP growth, even including the wartime loss of industry.
I guess being in bed with the economic policies of Stalin is oh-so-much-worse that being in bed with the economic policies of Yeltsin, who managed to kill off people at a faster rate than the Otets Narodov, and got started sooner too. What do you know, Stalin's retrospective approval rating is about 20 times as high as Yeltsin's.
Wait, I forget, in the West, Stalin = evil. Anybody associated with Stalin was evil too. Stalin lived in a secret Fortress of Evil surrounded by a moat with crocodiles and laser towers to pick off starving peasants. Whilst sitting on his throne of human skulls, he would make personal phone calls to Paul Sweezy, Lex Luthor and mighty Cthulhu who waits sleeping in R'lyeh in order to better coordinate their plans for murderous world domination, when the stars are right.