@nprofile1q... J.P. Sartre, for one example? He defended Soviet system well into 1960’s. His particular argument was that we should not talk too much about the atrocities of Stalinism as it takes away hope from the workers in other countries.
That, or similar, was the position of many Western leftists. Sartre wasn’t alone - his position was shared by L’Humanite, as bitterly recalled by Arthur Koestler years later.
One notable exception was “The Practice and Theory of Bolshevism” by Bertrand Russell published after his trip to Russia in 1920, but that was it - an exception at that time.
https://www.gutenberg.org/ebooks/17350