The thing is, Kael has mentioned that a lot of the ideas for FfH came from his days of playing Dungeons and Dragons. That being said, if you're familiar with the dark elves of Dungeons and Dragons, you'd know that they are definitely not like their tree hugging kinfolk. Certainly not everyone will be aware of this. Just as an FYI, the dark elves that I'm assuming these were modeled from typically live underground like the dwarves and gnomes, so the elvish promotion wouldn't really fit for them even though they are in fact elves, just not elves of the forests.