Japan is 98% ethnically homogenous, with the remaining 2% primarily consisting of Koreans and Chinese. I don't see why Japan would have any need for a discussion on 'race'.
Japan is 98% ethnically homogeneous in part because of an immigration system that keeps foreigners from immigrating for work and in part because of lots of systemic racism - different from that in, say, the US, but still systemic - in Japanese society. It's not magic or an accident of history, it's due to social factors.
>because of an immigration system that keeps foreigners from immigrating for work
Okay so let me dispel this myth. I don't know when it started, how, and where, but Japan is not that hard to immigrate into if you have a job or are a student enrolled in a Japanese school. The biggest issue is probably the language and the fact that most jobs are in Japanese, but if you speak Japanese (or can find an English-speaking job) then it's not that hard to immigrate into Japan. Work visas are pretty easy to obtain. Permanent residency is relatively easy to obtain too, and even better, citizenship is even easier to obtain (although you have to renounce your former citizenship). With that in mind, the US are objectively harder to immigrate into compared to Japan, on paper at least.
Which brings me to...
>and in part because of lots of systemic racism
I think the main issue of Japan is just cultural and the language itself. A lot of what can come across as racism is just a misunderstanding of societal expectations and behavior. Language barriers are really hard to overcome and Japanese is one of the hardest language to learn if you come from an English speaking background (or most European languages, really). The fact that most people in Japan don't speak English well, and that they are a culture that is significantly different from a lot of the west doesn't help.
And yes, there is still quite a bit of sexism and racism (although I'd argue the latter is more from a position of "unknown" rather than actual hatred/disdain). Stuff is improving fortunately, but it takes time.
This said, I don't think racism and xenophobia as a whole, or the country's own immigration policies, are what are keeping Japan so non-diverse.
source: Live and work in Japan, speak Japanese. This is obviously just my opinion.
Although I don’t think any country should be obligated to take in foreigners if their situation doesn’t warrant it (such as being a small island nation).
I think what op meant to say is if there is little diversity then naturally there would be no debate. But indeed i agree they should at least stop making racist movies.
Boy do i hate race related debates. Why is race even relevant in this day and age? It’s all in our minds and it stems from primordial tribal thinking. Its like people from village A dislike people form village B because they will steal their women and hunt their game. Such basic instincts that we somehow havent moved beyond yet despite our tech progress.