Being actors who make their living pretending to be people they are not, I see no problem with a black actor portraying a white man if he is properly made up to look white.
In the past who can forget John Wayne as Genghis Khan or Robert Morley as the Emperor of China. Peter Lore as Mr Moto, and such.
I always thought it absurd that Hollywood couldn’t come up with enough actors of the character’s supposed race. And bigoted. (And that’s about the extent of my need for diversity in film, etc.)