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?
“Every time” is certainly an exaggeration. Just off the top of my head in a minute:
If I looked around further, I’m sure I could find more. All of these have variously been critiqued for writing, characterization, or pacing, but failed to draw attacks based on the ethnicity (or orientation) of their protagonists.
Is this kind of attack a thing that happens? Absolutely. Is it “every time”? No. I’d suggest it’s more often when a series goes out of its way to bludgeon the audience with a message related to it, or tries to sell a newcomer as a superior replacement for a legacy character, that people can get riled up.