though the skin change thing is pretty bad (I would have bleached her hair cause the dark spirit king's blessing is dark skin and Balck hair), I get it.
The whole point is that everyone is apologising to her post looking like everyone else. They could not accept her for her and only her appearance.
Also, Japan seems pretty xenophobic in general, that topped with ignorance (not understanding the whole big nose, big lip black man thing is racist) and the lack of people of African descent over there it makes sense this happened.