Well they have no experience in diversity so they can't really judge USA. Once I see Japanese and Chinese hugging it out then maybe I might take their considerations more serious. Japanese also treat their low wage foreign workers that work in Japan like subhumans. In my opinion they have no room to talk
I don't know how Japan treats low wage foreign workers, however a brother of a friend of ours has been living in Japan for decades. He married a Japanese woman and has two kids, yet stll experiences xenophobia against him. When the pandemic started some people were shouting at him to get out and go home while he was just on the way to work like everyone else. He is formerly Canadian. He loves the country (obviously) but does get confronted with xenophobia now and then.
Anyway that has nothing to do with this topic. However never really dealing with diversity and latent racism while growing up does make you less capable to understand the long ongoing situation. I grew up in the Netherlands with plenty of stereo types about Poles mainly (migrant workers), later refugees before it turned onto Muslims in general. My grandfather, great man, but his ideas about black people were typical for his generation. There was a lot of friction between him and my mother and her family (She was born in Indonesia). It's easy to slip into "Oh they probably did something wrong, deserved it" which is at the heart of the problems in the USA. The initial mindset while going into a confrontation together with fear.
Racism isn't just openly spewing hatred against other races. It can be very subtle and plenty people don't even realize their prejudice, be it against black people, religion or police. Do you treat your family members the same as any random stranger? The police should and its not easy.