There are a lot of things a creator needn't explain to an audience. Otoh, if something one puts out garners a reaction like that, it's worth examining, at the very least. You seem to think that it's not worth criticizing? People coming into Elfquest for the first time might start with the Final Quest, picking it up randomly in a bookshop. That line might be the line that completely alienates them, or, worse, it might be the line that confirms for their subconscious, already operating within the framework of an already white supremacist society, that "pale skin" is a sign of superiority and evolution. Characters and stories might exist in the framework of their own worlds, but their audiences exist in this one, and that is something all creators must constantly bear in mind. Your audience will, if your work is any good, take the things you say into their hearts and minds, and out into the wider world, where it will affect the people around them. That's something you've known since you first started publishing, so it's difficult to understand why it's seemingly being ignored now.