I've heard an interesting take from an assistant to a lawyer who helped someone defrauded of money.

    Nobody ever wakes up in the morning and says, "What I am going to do today is evil, and I'm okay with that."
    When I thought through each of the examples of society-wide atrocities,
    examining them through the new lens I had gained in that deposition room,
    immediately I saw it: In every single case where people cooperated with evil, they used eloquent lies to assure
    themselves that what they were doing was actually good.