Ta-Nehisi Coates (my favorite blogger) has been reading Bloodlands: Europe between Hitler and Stalin, Timothy Snyder's book about millions of murders in Europe between 1933 and 1945.  The details shared by Coates are horrific.  The book lists so many atrocities, Coates worries it might numb the reader.  Still he says,

...I think Snyder frames the questions correctly--How can men commit such acts? The question is not answered by empty invocations of "evil" or vague invocations of "sociopathy." The question is not answered by memorializing victims (though this has its place) or the construction of national oaths (though that too might have its place.) On the contrary the question might best be answered, not by identifying with history greatest victims, but by identifying with its killers. This is in fact, as Snyder argues, the moral position.

He then quotes Snyder:

It is easy to sanctify policies or identities by the deaths of the victims. It is less appealing, but morally more urgent, to understand the actions of the perpetrators. The moral danger, after all, is never that one might become a victim but that one might be a perpetrator or a bystander.

Coates concludes,

I think that allows for a skeptical morality. I think that allows those of us on the socio-economic bottom to give up our righteousness, to understand that there is nothing super-moral, or blessed, or prophesied in being down here. The bottom is just the bottom. Can we truly say we'd be much different were we on top?