The article refers to the banality of evil in realation to Eichmann. There's actually been quite a bit of historical push back on this assertion, which in some ways has been used to rehabilitate Eichmann's image as a bureaucrat. Eichmann while not the chief architect, was definitely partly responsible for the Holocaust's "success" and actively climbed the nazi hierarchy by finding a niche to fill - exterminating jewish people.
I always thought "the banality of evil" wasn't about minimizing the horror of his actions. It's not saying "what he did wasn't so bad," but "these horrible actions were done not by an obvious villain, but by someone personally unremarkable."
In addition to the push back there's the fact that Hannah Arendt -- who coined the phrase "banality of evil" -- was also a lover of Martin Heidegger.
Heidegger was an enthusiastic Nazi and Arendt also defended him. Some people see the "banality of evil" book as essentially being a defense of Eichmann.
It should be in all standard encyclopedias, but it's certainly in Britannica and Wikipedia. Usually I like to cite Wikipedia, but I'll add Britannica in case people have conspiracy theories about Wikipedia. And you can read more about their romance in the other sources. The Slate article discusses her use of antisemitic sources in her books.
And people just ignore a number of very convincing anecdotes told to Lanzmann from Benjamin Murmelstein, someone who would know, including one with Eichmann personally helping trash the inside of a Vienna synagogue on Kristallnacht.
