Neo Alice
Mahō Shōjo
I think what is being discussed is implicit bias. What 4scorelightnings is trying to get across with the anime = Japanese comparison is that there is no contextual reason for the character set in a Japanese setting to be anything other than Japanese.
So if you look at the art and just assume that everyone is white that points to a subconscious assumption on your part that white is the default color. Therefore non-white characters have to be obviously represented in some way to count.
But as the saying goes “if it moves like a duck, and quacks like a duck, then it’s a duck.”
Naruto is a blue eyed blonde, but he also has a Japanese name, he very clearly lives in a fantasy Asian setting, and there is from what little I know of the series no indication of any kind of European/Western place existing.
This is a fantasy world with effectively magic powers and weird demon beasts. It’s not a huge leap that people can be Asian and also have naturally pink or blonde hair.
I said Naruto for a more famous example, there's perfectly regular slice of life animes set in modern japan with no superpowers nor external factors whatsoever (that even are about science) and still there's these type of characters with physical characteristics that don't fit the japanese realistic appearance nor any realistic appearance at all.
The duck test is actually "If it LOOKS like a duck, swims like a duck, and quacks like a duck, then it probably is a duck." If you see a parrot quacking and swimming like a duck you aren't going to think it is a duck, right? You'll asume the parrot has heard a duck quack and it's mimicking the sound.