Here's the flaw with that argument. "Good and evil" are subjective (Things are more "grey" in reality).
cite your sources, and don't tell me Palpatine. It could be that you're treating as subjective, something that is merely unknowable. What is good and evil, and whether or not they are subjective, is the fodder of most philosophy. Furthermore in my experience most philosophy is really about one question: "What gives value to human life?"
None of this is pertinent in D&D because good and evil are explicitly objective in this setting, and unlike in our world, those 'people' aren't human. One of the reasons I brought up Mass Effect is because science-fiction deals with this dynamic in a slightly less fraught way. Stories about heroes dealing with icons from folklore are already going to be easily seen as allegory for the real world, but spacemen making first contact with an entirely new form of life are easier to treat for what they are, something completely alien to our own experience. It's very pithy to think that everyone is human, if they are sentient how can they not be, but what if sentience is a concept that we take for granted in this way. Even with free will your essential makeup in D&D can be inherently good or evil, there's no way getting around that.
Also I'm not an expert in Tolkien cosmology but I do think Sauron is in league with or is continuing the work of literal Satan, and not cool neopagan Satan either.
As for the Witcher, I think this brings up a concept I haven't seen too much around here. The idea that not only can individuals, races, and societies have alignments, but also worlds. Or in D&D, planes of existence. The Material Plane is tabula rasa but it is influenced by every plane of existence, among these are the planes where lawful chaotic good and evil stem from, think on that the next time WotC tries to downplay alignment.
And the most important take away of all...give us a romanceable dragon please. I'll also accept a mermaid~but I've said too much.
