I'm a non-Japanese Asian American who's lived in Japan for almost 10 years. My graduate thesis was actually about the perceptions of Asian-Americans/Canadians in Japan.
I'm not going to condone any particular viewpoint one way or another, but here is why I think it's difficult for most Japanese people to immediately sympathize with the argument made by Asian-Americans for more representation in Hollywood:
Japanese rarely if ever group themselves in with other Asians
In Japan, you are a foreigner whether you're from Korea or Zimbabwe. Pan-Asianism is an idea that pretty much died out at the end of World War II. Some of the more cynical people in Japan might even view the Asian-American argument as other Asians (Chinese, Korean, Filipino, etc.) trying to take credit for something engineered by the Japanese. When Memoirs of a Geisha came out starring Chinese actresses, the lack of authenticity was noted. Inversely, Japanese people tend not to take credit for that was invented in other Asian countries in modern times because they genuinely believe it has nothing to do with them. Asian-American or Pan-Asian solidarity just isn't a common concept here.
The Japanese don't like fiddling in the politics or social issues of other countries.
Many people here prescribe to the reggienotmyproblem.gif mentality. Japan is the only developed country not to have officially expressed a particular viewpoint on things like Trump's Muslim ban or Duterte's drug war. As a Western-made movie based on a Japanese concept, many feel that the handover has been made and that anything that happens is exclusively a foreign problem. That goes for the plight of Asian-Americans, perceived or otherwise. Even Japanese-American internment during World War II fails to resonate in Japan as a topic of social struggle and few are outwardly sympathetic, if at all. Which brings me to my next point: many Japanese consider Japanese-Americans as foreigners/outsiders in certain senses. I personally think this is changing somewhat as Japanese who leave now tend to maintain stronger connections with their home country, but to unilaterally shoulder the Japanese with the responsibility of ensuring Asian-American representation in their pop culture isn't the right approach.
As an Asian-American, I personally wish for more representation and there are times when I actually even feel resentment toward things I perceive as white privilege or whatever you want to call it. But at the same time, expecting them to immediately understand the issue and agree with our viewpoint is little more than an American viewpoint getting pushed onto another country without proper contextualization and itself can be seen as a form of cultural imperialism. It's not such a clear cut issue.
