Every good and bad thing that exists in the real world also exists in our games; human nature isn't altered in the campaigns we run... that doesn't mean we dwell on most of it all that much, but we don't have any "taboos" on any subjects that we prohibit anyone mentioning. Murder, bigotry, slavery, torture, cannibalism (ghouls come from somewhere!) all of these things exist in the worlds of our games... in other words, Evil exists.
In my opinion, pretending that these things somehow didn't exist would only seem to cheapen the nature of Evil. Most Evil tends to be far more mundane than world-conquering demon worshipers, of the kind that we encounter in real life. Pretending that something doesn't exist doesn't make it go away, and pretending that these things don't exist in the game would only make it feel shallow and unrealistic to me; I can accept the existence of magic and dragons as part of the rules of an alternate reality, but trying to pretend that human nature is so drastically different that bigotry doesn't exist? That's just too much for me to swallow.

In alternate campaigns we try to have a good mix of down n' dirty tomb raiding, where events of questionable morality are more evident, intermixed with the kind of lofty epic struggles of Good vs Evil where such things just aren't mentioned.
Now if you're asking whether or not these are things
PCs participate in, well, not unless they are Evil (yes we allow Evil PCs; I play them sometimes and it can be refreshing) but even then the occasional Evil PCs we have tend to be more "tasteful" (for lack of a better term) and not to go in most of those directions.
But in any event, most of these things aren't something we usually dwell on that much (however, some are essential elements of history) but we would absolutely never act like they don't exist. They are part of human nature, and pretending like they aren't feels like it would only cheapen their existence in the real world... like making a movie set in the pre-Civil War era and pretending there was no slavery.