Are these acts really equal on the evil scale?

Thanks to Anne at PalmTree Pundit, I found my way over to a very interesting New York Times article which wrote about forensic scientists who are finally willing to use the word "evil" when talking about the most heinous killers:

Among themselves, a few forensic scientists have taken to thinking of these people as not merely disturbed but evil. Evil in that their deliberate, habitual savagery defies any psychological explanation or attempt at treatment. Most psychiatrists assiduously avoid the word evil, contending that its use would precipitate a dangerous slide from clinical to moral judgment that could put people on death row unnecessarily and obscure the understanding of violent criminals. Still, many career forensic examiners say their work forces them to reflect on the concept of evil, and some acknowledge they can find no other term for certain individuals they have evaluated.

So far, so good. Perhaps because I was raised in the shadow of the Holocaust, with many family members from my parents' generation having died in the camps, and many friends and family who experienced the camps, I've always believed in evil. You can give it as many fancy scientific names as you want, but a normal person knows evil when he or she sees it. That's why I was surprised to see this little discussion thrown into the article:

Western religious leaders, evolutionary theorists and psychological researchers agree that almost all human beings have the capacity to commit brutal acts, even when they are not directly threatened. In Dr. Stanley Milgram's famous electroshock experiments in the 1960's, participants delivered what they thought were punishing electric jolts to a fellow citizen, merely because they were encouraged to do so by an authority figure as part of a learning experiment. In the real world, the grim images coming out of Iraq - the beheadings by Iraqi insurgents and the Abu Ghraib tortures, complete with preening guards - suggest how much further people can go when they feel justified. In Nazi prisoner camps, as during purges in Kosovo and Cambodia, historians found that clerks, teachers, bureaucrats and other normally peaceable citizens committed some of the gruesome violence, apparently swept along in the kind of collective thoughtlessness that the philosopher Hannah Arendt described as the banality of evil.

Now, maybe I'm biased because Abu Ghraib was committed by American forces, but I can't shake the feeling that no matter how brutal, disgusting and, mostly, stupid the conduct at Abu Ghraib was, it cannot be placed in the same sentence as beheadings, with the implication that the two are morally equal. And then to follow that reference with allusions to Nazi death camps, and purges in Kosovo and Cambodia -- again, I had this horrible feeling of cultural and moral relativism. How can the author of an in-depth article about true evil be so morally blind as to throw in a reference to what is, in the grand scheme of things, "merely" scandalous, brutal and stupid conduct? Again, I don't want to excuse the perpetrators at Abu Ghraib -- what they did was unbelievably mean and, again I come back to this word, stupid, but it is not morally equally to beheading, cannibalism, gas chambers, etc.