Oh, evil is most definitely a thing. Or, to be more precise, an action. What about things like the Holocaust? Stalin's purges? Pol Pot? Or your more garden-variety murders, rapes, assaults, etc. Are you suggesting those are not evil? How could they NOT be? To suggest that something isn't evil is to imply that it's GOOD, and I can't conceive how any rational being could deduce that any of those things are good.
WWII is an interesting example. If, as you say, ‘evil is most definitely a thing’ or an ‘action’ then what about dropping nuclear bombs on cities, killing mostly civilians in the process?
By your own list of ‘actions’ you consider ‘evil’ I think that most certainly qualifies as ‘evil’. And since you’re not interested in looking at the motivations behind the act, well, there’s only the act to speak for itself, isn’t there?
Personally, I don’t believe that ‘evil’ is a thing. It is, essentially, an expression of a specific point of view (individual) or a common consensus (group). We, as a society, define what we consider to be ‘evil’. But it is merely a means of describing certain types of behavior that do not conform to what we believe to be ‘good’.
I don’t tend to view people as inherently ‘good’ or ‘evil’. I think it simply doesn’t explain the way the world works and the way people behave day in and day out on this planet. People have certain motivations, needs and desires. Their lives are largely defined by trying to satisfy these in some form or other. I think this applies to people who are ‘good’ as much as it does to people who are ‘evil’.
The question of who falls into which particular category depends on your own perspective and your social values. Or another way of putting it is that people tend to be on different parts of the curve describing what it means to be human. For me, what makes Hitler’s actions so terrible and unbearable is NOT that I think he was ‘evil’ but to think that he was a human being just like myself, just like everyone else. To think that such atrocities could come from one of us is what’s frightening in my mind.
And that, I guess, is why I find villains (to get back to the thread) whose motivations I can see and ‘understand’ so much more intimidating and effective. “The Emperor” is a cool villain, for sure. But, honestly, I don’t find him to be very scary. He’s a comic villain who provides a few chills but most of all some fun, really.
I find a character such as Helena Cain from nuBSG, for example, to be far more effective as a villain (some will probably argue that she isn’t but that’s for another discussion, I guess). You can see why she does what she does. And that’s what’s frightening in my mind.