If we take, for the moment, that the Greeks of the time thought this behavior was okay, even laudable, that leaves us with the obvious question - were the Greeks correct in that thinking?
It seems to me that a position amounting to, "If I do not think my behavior is villainous, then I am not a villain," rather defeats the purpose of having the words hero and villain.
Agreed.
I'm firmly on the "The Greek Heroes are really anti-heroes"... they are, in many ways, the epitome of xenophibia. The Greek Philosophers' civilization's rules for life would be considered criminal acts today... slavery, corporal punishment¹, gender discrimination, pederasty², child-marriage³...
So I find
@MGibster 's appeal to the Greeks as entirely unconvincing; the Greek's definitions of good and evil are not the same as modern Western Civilizations.
The appeal to Ayn Rand? Well, even a broken clock is correct at least once per day. (I've seen enough 24-hour dials...) She takes a position that is common, but not borne out by research for teens and older, that games activity trains the player to do those things in real life. For some, yes - which is why I cringe when people have kids under 8 playing RPGs, playing violent videogames, or learning combat arts... because there is significant correlation for the under 8 group, it's weaker the older the player. (I can't open the textbook PDF anymore to get the citations.)
¹: The legality of it varies widely, from none at all in some US states, to only if culturally or regligiously inherited, and/or "only if it leaves no mark."
²: I'm not going to explicate it.
³: As in, under the age of criminal adulthood (16 or 18 in the 'States, by state). Still practiced in some states in the US... one still allows age 14...