Ofc race and gender matter.
If I make a movie about Japan, I probably want Japanese people only. There is no reason for me to include africans.
You get what I mean.
The same goes for Star Wars. Maybe black people are just way less common in the Star Wars universe than anywhere else. There is no reason to assume that black people are just as common. Actually if you watch the movies, black people are extremely rare.
So why should there be so many black guys now?
Equally, I think I have not seen a single Asian guy in star wars, until that new movie.