Board Thread:General Discussion/@comment-25266931-20170217011737/@comment-14138255-20170227221710

Most of Japan's racism is unintentional or in the case of China/Korea, fueled by lingering animosity passed down from their parents and grandparents (as: "don't marry a Chinese girl" and "don't hang out with those Japanese boys"). The Chinese and Koreans are much more racist against Japanese than the other way around (for understandable reasons), but its declining on both sides.

As for reasons against brown people, that's very unintentional, as there are very few foreigners, let alone people of color.. They have such small reference pools they'll think they look the same (though many adults know better and discourage it).