Alzrius
The EN World kitten
Not quite the same, but this is similar to why I've never been convinced by the idea that "it's impossible to have an inherently evil race that has free will" argument. It's entirely possible, it just requires some imagination, which is central to tabletop RPGs anyway.I find this easy. The orcs happen to be evil. Most encountered are in face footsoldiers of evil wizards or are part of an invading force.
For instance, let's grant the premise that orcs have free will. But even having established that, every single orc in the campaign world has (and always has) chosen of their own free will to be evil. That's the moral equivalent of rolling a d6 ten thousand times and having it come up as a 1 each and every time; technically not impossible, but so completely improbable as to be beyond some people's suspension of disbelief.
But for a lot of other people, I suspect it's no more beyond their suspension of disbelief than a barbarian who swan dives off of a cliff that's two miles high (20d6, average 70, falling damage) into a pool of lava (20d6, average 70, fire damage) and can then swim to the edge, pull himself out and engage in combat, because he still has hit points left. (Or, for that matter, no less an issue than the prices of goods being static and unchanging in defiance of market forces, which don't seem to exist.)
Now, that's a separate issue from people not liking that idea, but insofar as "free-willed creatures that are inherently evil is an inherent contradiction, and so can't exist" goes, that may be true in reality, but the nature of fantasy is to neatly sidestep the conventions of reality.