It's not simply a fact of elf being black or not.
This retarded pleasing of minorities is ruining the Cinema and most tv shows.
Especially if you are adapting something, forcibly putting someone who doesn't fit the role just to please someone is fucking retarded.
But that's only my opinion, doubt anyone cares or agrees.
Well, I agree, but I also disagree with that.
Adaptation is, by definition, a fucking adaptation. It's not supposed to be a copy/paste. Different medias demand different approaches. One Piece worked being goofy and having a bunch of comic faces, but trying to turn it into a Live Action just doesn't work if you try to edit some giant mouths every time someone smiles on the show.
Don't get me wrong. Big Companies don't want to be "cool" and "representative" or anything like that. They want money and they make a bunch of calculations and come to the conclusion they will make more money if they make such adaptations.
SOMETIMES they get things right (Black Panther movie), sometimes it becomes some stereotypical cringefiesta (Captain Marvel).
Tolkien was, for better or for worse, a man of his own time.
It's not uncommon that his stories have traces of prejudices that, at the time, were not as apparent as they are today. Adapting these things is pretty ok. The problem starts when you think you already did your job purely because you decided to cast a black dude to play an elf, but the show is still a mess.
Think GoT. The idea of "empowering" women through Arya, etc.
They completely butcher a plotline they DECIDED to create (there's no night king in the books. that's a show thing). The SHOW decided to turn Jon Snow into "the hero". The SHOW decided to create this antagonism between Jon and the Night King. The SHOW also decided "fuck it, it will be surprising if Arya do it instead! Yeah, Girl Power! Damn, I'm such a feminist guy!".
See what I mean?