I'm not the person you asked, so I can only answer for myself. Previously, I had viewed Nazism as more of an aberration that overtook one society, and was the sole cause of the brutality of the Holocaust. Learning about the other forms of brutality that played out over the exact same geographic area, from a political direction that claims to be the arch-enemy of Nazism, points out that people's political representations are often quite distinct from the material effects they enact on people's lives. The Holodomor was not widely reported, and in fact covered up by the few Western journalists that witnessed it, and in the informational blackhole caused by Stalinism and the abduction, imprisonment, torture, and frequent death of anybody who stood out, much less spoke of the massive damage caused by Stalin, well, the full nature of what happened was not visible to the world until the fall of the USSR. The eyewitnesses to the starvation were often silent to their own natural death a decade after the fall of the USSR, due to the depth and depravity of the oppression of expression that happened in the USSR.
Basically the book points out the same lessons that Hannah Arendt and others have been pointing out for a long time, that such mass death of innocent people is quite possible even outside the strange ideologies of Nazis. The conditions for evil are quite endemic to the human condition, especially in those that abandon truth in pursuit of political strength.
Thanks for responding that makes a lot of sense. I think you're right about that, and if we view these movements as cults rather than political movements then it starts to make sense how different projects / ideologies can end up at the same conclusion of destruction.
Basically the book points out the same lessons that Hannah Arendt and others have been pointing out for a long time, that such mass death of innocent people is quite possible even outside the strange ideologies of Nazis. The conditions for evil are quite endemic to the human condition, especially in those that abandon truth in pursuit of political strength.