Any documentary about Cuba shot in 1987 could have been used either by USA or USSR as a propaganda tool. Although at that time, USSR was on the path of liberalization already. US did not like the idea of having a Communist country in the backyard and trained many of the Cuban refugees, planning the overthrow of the Castro regime. As a consequence, Cuba was the site where the Third World War almost broke out in October 1962. The propaganda criticism is unfair given the fact that Castro and the directors of the prisons are questioned about the prisons, but they obviously deny everything trying to cover the Communist reality. So, I don't think propaganda is the point of the movie. People are escaping Castro's Cuba and that's a hard fact.
As someone who comes from a region which was for five decades under Communism (i.e. Eastern Europe), I see a lot of similarities between the post-revolutionary Cuba and the attempt to create the Homo Sovieticus. Once again I am convinced that Communists are afraid of ideas, despite their claim that ideas don't matter so much in history. The plight of the Soviet and East European dissidents in labor camps is strikingly similar to that of the current Cuban dissidents. The former were escaping to Western Europe, while the last - to USA. China, Vietnam, North Korea, Cuba are of the same kind. However, sooner or later, they will have to change, same as Gorbachev tried to reform the Soviet Union and failed. Although Castro's Cuba was probably closer to the sultanistic regimes of Eastern Europe, most notably Romania. I think once the Castro family loses its grip on power, the whole regime might collapse. Overall, I consider that this is an excellent movie about the prison system in Cuba, but I admit that I might be biased because of my Eastern European background.