A) Hollywood isn't here to be a social force. It's here to make money. Casting a white woman in a movie that will be primarily aimed at Americans will make more money than a casting a more "appropriate" person in the role. ie: Oriental. While MOIVES and CINEMA can be powerful social forces... those are separate from Hollywood. Hollywood = $$$$$$$$$. That's why we get so much stuff aimed at teenage kids who literally don't know a good movie when they're presented with one. Most of us didn't know good movies from bad movies until we saw dozens of bad movies, saw a few good movies and learned how to tell good from bad.
Think of Hollywood as Matthew McConaughey from Dazed and Confused. Every year there's a new crop of kids who haven't seen a terrible Michael Bay movie yet, but it looks awesome in the trailer so they line up to go see it. Boys, mostly; the big money-making movies are always aimed at boys. (white boys, to be more precise) Boys don't care that it's got sexist jokes in it. Boys don't care that it's got racist jokes in it. They don't even understand what racism and sexism are, for the most part. It's loud, it's crude, it doesn't require any sort of deep thought, just go with it and enjoy it. Maybe in 10 years they'll look back on the movie and say "How... did I ever think that it was actually funny to see a transformer with giant testicles?" or "Those twins ... ya know, I've seen some actual racist shit, and those twins... I dunno man, if they aren't outright racist they're somewhere on that family tree.".
But that same year, there's another crop of kids who haven't seen a terrible (insert new director who makes terrible movies aimed at kids, mostly) move yet, but the trailer looks awesome. And David Wooderson is sitting back there going "Teenagers. Every year I keep making billions of dollars, and they just stay the same age."
That's Hollywood. Don't expect Hollywood to care about social causes at all; the best you can hope for is that a cause you believe in will catch the attention of a Hollywood studio looking to win an Oscar. Beyond that, don't expect a thing.
Now if you want MOVIES to help with social causes... you're going to have to out there and make your own movie. Or find someone who's making a movie you believe in and help them make that movie.
B) The segue into the sexism/feminism/gender demographics of Hollywood is... a bit of a red herring in this article. I will wholeheartedly agree that it's an important issue to discuss, but including it into this article is just going to give people who want to scream about Feminism/Feminists/Misogynists/Sexists a reason to scream about those topics, and ignore what I gather is supposed to be the main thrust of the article - that there is a problem with casting a white woman in what has been an Asian woman's role up to now.
Also, the discussion about women in Hollywood's backroom/boardroom? That's going to have to be a far larger discussion about women in backroom/boardrooms in general, not just Hollywood. Hollywood isn't different enough from Wall Street or K Street or Silicon Valley to warrant its own separate topic.
c) Rinko Kikuchi
Other than Pacific Rim, what has she been in to show she can act? She's cute, she's Japanese, she's able to deal with choreographed fight scenes impressively, but... okay? I liked her in Pacific Rim, but I wasn't impressed with her. Or any of the actors, really, beyond Idris Elba. (I liked most of them, but liked is not the same as being impressed.) A big meh for me on her for the Major.