You could debate this question back and forth, and undoubtedly score valid points for each point of view.
There's no right answer, just preferences. My preference would be that you should still be able to have a lot of fun and win the game even if you don't go through the intended First-Person Character Arc.
That is, even if you don't help the forest nymphs, you could still win the game. It would just be lot tougher and not as fun.
Perhaps we'd draw the line at murder. If you killed more than three of them, you couldn't win the game.
Again, these are just preferences. The game could be designed in many other ways.