Frankly the whole ‘cultural appropriation’ thing turns my stomach, it’s corrosive and small minded.
It can be quite a problem though in some contexts.
What if a basic white middle class singer/songwriter decided to release a drill album? Objectively might be outstanding and do well commercially. But in doing so he’s used his existing advantages to the detriment of another group of musicians who then would be unlikely to succeed as the market is already flooded.
In this case some people are arguing that in this case there was an opportunity to cast someone ‘black’ and that instead they’ve given it to someone ‘brown’. If you’re on the receiving end of the discrimination that sort of thing probably matters.
There are other roles where casting could be more gender/race/orientation blind. Would it really make a difference if Möbius in the matrix films was a white lesbian? But it wouldn’t work if Laurence Fishburne tried to play the lead in a biopic of Margaret Thatcher.