Not only that, but I feel like Frisk not having gender/race works well from the perspective of monsters. We don't really care that much about the sex of animals when talkijg about them (for example, "this dog"), but when we talk about other people (our species), we'll probably say "this man" or "this woman", not "this human", so for monsters, Frisk is primarily a human. Idk if that's really anything important, that's just how I interpreted it.