This is Hannah Arendt's thesis behind "the banality of evil"[1]:
> Arendt found Eichmann an ordinary, rather bland, bureaucrat, who in her words, was ‘neither perverted nor sadistic’, but ‘terrifyingly normal’. He acted without any motive other than to diligently advance his career. Eichmann was not an amoral monster, she concluded in her study of the case. Instead, he performed evil deeds without evil intentions, a fact connected to his ‘thoughtlessness’, a disengagement from the reality of his evil acts. Eichmann ‘never realised what he was doing’ due to an ‘inability… to think from the standpoint of somebody else’. Lacking this particular cognitive ability, he ‘commit[ted] crimes under circumstances that made it well-nigh impossible for him to know or to feel that he [was] doing wrong’.
> Arendt dubbed these collective characteristics of Eichmann ‘the banality of evil’: he was not inherently evil, but merely shallow and clueless, a ‘joiner’, in the words of one contemporary interpreter of Arendt’s thesis: he was a man who drifted, in search of purpose and direction, not out of deep ideological belief.
[1] https://www.britannica.com/story/what-did-hannah-arendt-real...