I can understand looking back to them for some useful stuff. “Commieblock” housing served a purpose at the time, for example. They brought huge masses of people into an urban environment with indoor plumbing, electricity, and climate control, which were not a given in their previous living situations. They were meant as an interim solution to last a few decades. For what they set out to do, they were a great success. The only problem was that the followup to better options was never done.

But the Leninist/Maoists can never leave it at pulling out successes like that. It’s almost always “America bad”, “Holodomor isn’t real”, or “Cuba only sucks because of sanctions”.