Earlier quoted context omitted.
None of the countries you mention have ages old strong own culture to preserve really (except first nations but for various reasons their culture is not US or Canada culture). So Japan's policy is not unreasonable. You can become a proper Japanese if you want to (are willing to culturally integrate), it's just that not many people do. Without it you'd be trading off death of country for death of culture. Contrast to…
> You can become a proper Japanese if you want to I'm really not sure about that. I'm a white man with red hair, I'm pretty sure I'd always be "otherized" in Japan, as would most westerners.
The question is legal equality, which seems possible and not depend on color of your hair.
Of course some Japanese will treat you differently. They will also otherize and treat differently even their fellow ethnic Japanese of other social classes. But I think this is not really different from British, Russian or many other cultures (maybe except US or Canada which are more melting pot like). It's just harder to notice from inside the culture.