The fact that HBO was able to create such a believable depiction of the Soviet reality, shatters the simplistic propaganda message of "We are good, they are bad". It shows that UK and US people can tell a story that hits so close to home for every Russian person, and no official historical Russian movie of recent time was able to do anything remotely close. People who are tired of the propaganda message, seek the truth, and the contrast between Chernobyl and propaganda movies is striking.
It is hard to demonize the West, if the West tells you such a realistic story of your own past.