I think you've misread my post. I gave two examples of a dungeon that doesn't require "killing goblins for no raisin is Good actually". One was "it's full of inherently inimical beings", and the other was "they're actively doing something bad, not just existing".
Now IDK, maybe there are somehow a lot of great dungeon ideas that rely on "the foes are just sitting there existing" to work and would be ruined by "they're burning down outlying houses / they're kidnapping travelers into slavery" / "they're blockading food shipments so everyone starves" / etc. But I doubt it.
Incidentally, by the definition of evil you're going by, Hobgoblins who were kidnapping people to work to death in their mine would be Neutral, right? Because they're doing it for material benefit to themselves, not just out of sadism.
But now that I think of it, there's a much more significant problem I have with your argument -
You're determining Good / Evil primarily (entirely?) off motivation, and I don't think that's a sensible standard. While motivation is part of how I'd judge an action, the actual action itself is the more important part. Saying that "all pragmatically motivated actions are morally the same" seems nonsensical on the face of it.
For example, are you saying that there's no difference between delivering mail to people (because you're a postal worker and you get paid for it) and assassinating people (because you're a hit-man for the mob and you get paid for it)?
Even the most sincere motivation only goes so far - if a serial killer turns out to think that "only people who get murdered go to heaven, so I'm helping people!" that at best means they're too insane to stand trial, not that they're really a good person.