To expand my comment, the problem is not that it criticizes the soviet regime, that is OK and even needed.The big problem is the total lack of nuance which robs the work of any artistic value. When you read non-fiction and fiction soviet authors (Chekhov, Dostoevski, Grossmann, Zhukov, Bulgakov) there is always criticism of the government in general and the individual in particular, to different degrees, but there is also a human side present, this human warmness. Yes, the bureaucrats suck and the party establishment are bastards, but summer in the dacha is fantastic, getting drunk with friends is a brotherly experience and there is Masha waiting for me hopefully to form a nice family. All of this is mostly absent or totally disfigured in western authors treating soviet themes, this work one of the worst exponents. The soviet union portrayed in Rocky IV and Ivan Drago are more credible and three-dimensional than any character in this work. The people are only corrupt, incompetent and bad to the core (meany meany commies) or helpless victims of the system with 0 agency whatsoever. It's painfully obvious the author has not clue about the actual psyche of a soviet citizen or functionary.
For an example how to not do that, all one must do is read any of the authors you mention (or Tolstoy, Chukovskaya, Gogol...) Tolstoy in particular has a knack for painting the interior psychological worlds of his characters fluidly and from a place of deep empathy.