I'm sure whatever I may write here will be taken as too general and sweeping by some, and too specific and finger pointing by others. But thats where we live in life, those general areas that define decency, and when we stray from there, fingers point at us.
Japan is a racist society? Is that news?
As a black guy, what do you do about that? Do you not teach there? Or do you take whatever job that may be offered to you, and convince them there's no point in being racist? Is there another option? Write articles for publication about the problem?
Organise demonstrations? Petition organistions that support racism in Japan?
Asia is such a tough place for any non-white to teach, or to work, or to live, or to socialize, in any field. Will it ever get better? Probably not any time soon, would be my guess, considering world history.
If anybody ever finds a place to live--other than the arctic regions--that doesn't have roaches, rats, racism, violence, disease, deception, dishonesty, war, let the rest of us know.