Angie Han, writing now for Mashable, has a piece on why most excuses people make for racially insensitive casting are bunk:
Hollywood’s racial bias comes in many forms. Sometimes it’s “whitewashing” — casting a white actor to play a character who was originally conceived of as non-white, like the Major in Ghost in the Shell or Light in Death Note. (John Oliver has an excellent primer on the industry’s long history of whitewashing here.)
Other times, it might be favoring a white lead character in a narrative that borrows problematically from non-white cultures — like positioning Iron Fist’s Danny Rand and Doctor Strange’s Stephen Strange as the ultimate practitioners of mystical martial arts that they learned in made-up Asian countries.
Perhaps most insidiously, it can also mean simply overlooking POC talent, and defaulting to white characters and white actors time and time again, even when there’s no narrative reason to do so. We adore Tim Burton and the Coens as much as the next person, for example, but it’s hard to deny that their films tend to be pretty homogenous.