I unfortunately have not read the book but had the pleasure of watching the movie last night. It disturbed me to the core as it should have.
I have seen countless 'horror movies' of mans inhumanity from ideology - Shindlers list, The Grey zone, The Pianist, The Killing fields etc. We must never forget our past, history is important and it's good to see the truth about the other ideology of horror - communism. Nazism was soundly defeated and is dead and buried, but we left it's evil twin alive - communism.
Communism is making a come back in the west, popular with bored naïve youth culture, Che Guevara t-shirts, red sickle flags, antifa etc. The suffering of left wing & right wing ideologies knows no bounds. These books and movies are warnings that we must take heed of. We cannot revisit this dark chapter.