Interesting watch, and good topic for discussion! While I completely agree with what you're saying, I still think there could be exceptions. For example, cosmically EVIL beings like Demons and undead could easily act evil for the sake of being evil.Likewise, I think wholly alien entities could behave in ways that we can't begin to understand, yet we interpret as evil. Who knows why Illithids do what they do, or what the motivations of that Beholder might be. Their goals make sense to them, but they're simply beyond our grasp. One needs only look at the disparity in various human cultures, and what behaviors or motivations we can or can't relate to.That said, I don't think anyone should abuse what I just said, or use that as an excuse for sloppy writing. A good adventure should indeed have NPCs and villains we can (most of the time) understand. That makes them more human, and the world more believable.