the concentration camps, jails and torture chambers of a socialist state are not the same thing as identical things that, under capitalism, are damnable.
the CP´s around the world sticked to that behaviour mentioned above throughout all their existence, not only during the time of stalinism.
i remember, when in the 19-70ies &early 80ies, the CP´s used to argue, that nukes are only dangerous in capitalist society, but not in the "socialist" countries. cause in the west, working 4 the profit and in more haste, the building of nukes wud be done less exactly than in USSR, 4 example (they also ignored that the west was technically more advanced). and then, the nuke catastrophy in tchernobyl, USSR! i remember how speechless it left the german CP.
(on the other hand, all those who nowadays only talk about tchernobyl, "forgot" that the first big nuke accident happened 1979 in harrisburg, USA!)