This is what Banality of the Evil was all about. The idea that people who do evil things is different from people who do not is what allows those awful things to happen. Because that idea stops us from examining our own cognition for signs of conformity and groupthinking.
If we start recognizing that we too are capable of awful things all while believing we are doing good, we can start self examining our ideas, motivations and behavior, to catch ourselves before we embark on such grouptrips.
If we start recognizing that we too are capable of awful things all while believing we are doing good, we can start self examining our ideas, motivations and behavior, to catch ourselves before we embark on such grouptrips.