Could it be said that this is a pattern or that someone who comes to this conclusion is exaggerating?
For example, in many animes the characters are Asian and right-wingers don’t seem to mind. Maybe because most of the characters appear to be white, or because many Japanese animes have an actual cast of white characters. They don’t seem to mind if in a fictional world all the characters are white or Asian, but on the other hand they would mind if in the fictional world all the characters were black or had dark skin. Is this really a fact or an exaggeration?
With the low level of detail that’s used for most anime faces and the wild (by Japanese standards, anyway) hair colors, it’s usually pretty much impossible to tell without context whether a character is meant to be asian or european.
On a more ideological level, Japan was allied with Nazi Germany and committed a lot of atrocities back then, and they always had strong anti-immigration policies and an advantageous position to enforce them (island nation, difficult writing system etc.).