reference to the 'banality' of criminals we prefer to disassociate ourselves from reminds me of Hannah Arendt, the influential German Jewish philosopher and her famous book Eichmann in Jerusalem: A report on the banality of evil. She observed at close quarters the trial of Nazi officer Adolf Eichmann, kidnapped from a Buenos Aires street and taken to Jerusalem to stand accused of his crimes in the Holocaust.
Here is a link to some biographical and educational material about Arendt's life and work. Her notes on Eichmann and her subsequent book (revisited and reviewed here at Steve Reads) spoke of how easily a figure of such evil fitted into the world, how he seemed too ordinary to be evil, and in many ways the difference between he and we who think of ourselves as being outside of such capability are never as great, or as concrete as we think. It is an uncomfortable read, and resonant and disturbing in far wider contexts than war crimes.
Misuses of power and the exploitation of uneven power relationships are all around us. We stand righteous against bullying then watch reality television shows that ridicule people perceived as weaker than 'us' or just different. We ask how bullies are created then back politicians who exploit existing prejudices against the vulnerable (unemployed, beneficiaries) for electoral gain. We talk of our collective generosity then try to drive down the wages of the lowest paid among us, for the 'good of the country.' I'm also puzzled by our revulsion of violence against children, then our championing of it with all sorts of euphemisms from 'disciplining' to 'teaching hard lessons.' Language is such a malleable tool, it can wrap acceptability around almost anything.
After all, Eichmann believed he was one of the righteous.