Where those black people have gone to when the story continued? You can't do this, without knowing the certain backlash. lso forgot that dwarf woman were already established to have beards. Both in the book AND the movies, so now the narrative is just broken for the sake of being broken. You also forget that this is an already established story, and not a new one. Your options are limited in what can be changed. The prime example I can bring for this is that in Brandon Sanderson's Mistborn series. 2 metals related to power were accidentally swapped in print, and now he's not changing it. It makes that power system weird, but it already got out like that so he's not changing it.

You ALSO forget that the LOTR universe already had dark skinned folks that nobody told stories about. This occasion of "blackwashing" is inherently political. It is just race swapping for twitter brownie points. IF you wanted to include black people, go for the lands that already had them.
I'm not a LOTR expert, but as far as I know those people also joined Sauron because they had their grievances with the north. The aftermath of that is one hell of a story to tell.

So no, you are wrong. It is inherently nothing but political messaging designed to upset people instead of being real fanservice that does the exact same thing that is on your label. Now this franchise is on it's way to become damaged goods like the rest.