Thing is, a thing in fiction doesn't actually need to involve humans at all to send a message. If a cartoon with talking animals and shit gives a PSA on how people have personal boundaries or something, that's still a message that can resonate with humans, yeah? Yeah.
The same principle applies here; if the only people in the movie with dark skin are either an inhuman, inherently evil soldier race or "evil men" (which I legit forgot about, it's been a while since I watched LOTR) while the good guys are all varying shades of light beige*, then that's not exactly a neutral thing when placed in a real-world context.
And like I said: I'm not saying it was intentional. But here's the thing; fiction can have unfortunate implications even when those implications aren't intentional. Stephenie Meyer intended for imprinting to be seen as platonic and beautiful; in practice, it came across as creepy jail bait wait. Death of the Author is a thing, and if I made a movie where the only people who look Asian are literal goddamn dog-men, it'd still be skeevy even if I legit thought it wasn't.
*if I remember correctly