They are very common in Germany and are in general really safe, the only crime going on there was smoking pot (which is not a crime anymore). I myself did not grow up in one, but many friends have and I still frequently visit people there. Floors, stairs and elevators are clean, neighbours greet you, when someone new moves in its common to help them as a neighbour.
Recently one of these houses was in the news "weißer Riese" in Duisburg because of crime. Now Duisburg is basically Germanys Detroit, used to be a coal mining city and has nothing else going on for it (still the homicide rate for Duisburg is 20x lower than for Detroit lol). And this house is 55years old and has been neglected by the developers, so rent for an apartment there is basically the lowest of any German city and in Germanys most undesirable city and somehow people wonder why there is some crime and this becomes the stereotype for all "commie blocks".
But for every commie block like that you get 1000 others that are really safe and clean, offer cheap rent, are energy efficient as fuck, some even have their own bus or train stations, big playground in the middle and usually more on the edge of the city so closer to nature.
This stereotype thing about commie blocks always reminds me of the american homeless people sleeping in tents in front of the "victims of communism" museum...
This is like saying the idea capitalism is incomplete because a true free market would soon sell fentanyl, organs and slaves, aswell as find every possible way to dump their trash into rivers. Both ideologies are merely mind games and contain abstract concepts like a free market (that is never truly free) or owning the means of production (that doesnt mean you can take your part of the machine home).
Also nowhere in the theory of communism is it mentioned that you should classify and control people. There are sentences like that by Marx himself but this is always a description of what he witnessed in his life under monarchy.
Just one example: You mentioned that communism should be classless but communists somehow love classifying. You got the first part partially correct, communism should try to eliminate classes. But do they love classifying? Absolutely not, they say its a necessary tool, in a non-communist society to be aware of the class you are in and try to break down class barriers around you, this achieving this classless society.
What you did, was saying: "Doctors love to pretend they heal you, yet somehow they love stabbing you" leaving out the fact that they stab you with needles/syringes in a controlled manner and they dont love the "stabbing" part, they love the part were after the stabbing you get better because of it.