I might be strawmanning this, but it's how I see these discussions:
A: We're including other races in the story because historically there's been a lack of diversity in movies and shows.
B: Alright, then work them into the story, introduce nations and factions whose background explains their appearance.
A: No, no, we are trying to show how people of all races are mixed in society, to represent the real world. <- Goalpost moved.
B: Alright, then you should feature actors from the middle and far east, south America, northern Europe...
A: No, no, we want to represent modern American society, and focus on American minorities. <- Goalpost moved again.
B: Alright, then you should feature native-americans, latinos...
And at that point I don't think I've ever seen a decent response. "They're too much of a minority" isn't a great argument when you're the one pushing for minorities to be represented in the first place.
The truth is simpler, certain minorities are trendy right now, and producers want to cash in to that.
That isn't necessarily wrong. It's greedy, creatively bankrupt, and slightly racist. But not ill-intended. Although it should be obvious to anyone when a movie or a show is sincere about their representation, and when they're just virtue signaling for money, and anyone not getting a paycheck shouldn't be parroting their excuses as if they believed them.
Infracted.