In reporting the minutes of the Eichmann trial in Jerusalem, Arendt begins incriminate some inequities in the side of the prosecution that wants to steer "his" trial. This is no longer the trial on behalf of humanity, but in the name of Jews; not the trial of a crime against humanity, but against Jews. The trial of mass barbarism through one man. Very practical to avoid digging and asking the right questions.
Hannah Arendt announces the era of the "banality of evil", that is to say no more evil by free will, one that we revolted at the same time fascinated us, but evil oath of allegiance; the little pseudo-Kantian obedience applied to the Reich, the hierarchy of the Reich, the laws of the Reich, the Cosmos of the Reich, and therefore: the Führer. The allegiance beyond any desire, any personal initiative, beyond the moral conscience, a small round-pusher pushy, meaningless, empty, sometimes grotesque, almost comic; authentic "Pontius Pilate" who said: "I am not guilty, I have obeyed, I wash my hands." The new nature of evil in the era of the masses.
The book's interest goes far beyond: it tells the successive stages of the destruction of European Jewry after the alternative failures (deportation to Madagascar, South America, etc.), and the downward spiral of engulfment, simultaneously with the fall of a martial and conquering ideology of a nation in a state of barbarism. A barbarity that was not the mere fact of German, but of all the collaborators, including many Jewish leaders themselves, who did not hesitate to send to slaughter "small" to preserve the "eminent"! The horror become a routine administrative component on the body of millions of anonymous martyrs.
For those continuing to think Hannah Arendt was pro-Nazi, anti-Zionist, she sought to defend or Heidegger indescribable stupidity, I suggest reading intensive refresher course.