In your example of MLK. Race would be important in that case because it is central to the story. Ghost in the Shell the alleged “white washing” is for a cyborg. The race of a cyborg is whatever they want it to be. It made no sense to make this argument for this movie. I assume this is a piece that Shea has wanted to write and was looking for the proper movie to do it for. He just chose poorly.
I am optimistic for diversity in regards to roles going forward. Look at the success of a movie like Hidden Figures. It’s success should send a message to studio execs that audiences will buy tickets to see non-white actors.