What I really liked about Ed Skrein's letter is that he didn't 'just' back out because of the uproar but it seems to indicate that he truly GETS it which is even more important imo. On top of that,he isn't a huge star like Scarlett Johansson for example so turning down a role in a (presumably) blockbuster is a big deal. I hope that this will be a lesson for other actors and the casting people themselves!