The furry subculture has a troubled relationship with “realism;” I want to introduce a distinction that helped me resolve the question in a satisfying way. When someone says “realistic,” they almost always are assuming that realism is just one thing. It is not: realism assumes that there is a reality and a portrayal and that the portrayal is more or less faithful to the reality. The problems with this approach crop up quickly when you’re talking about realism in the context of fiction or speculation or gedankenexperiments. Is Maxwell’s Demon realistic? Are the geopolitics of Middle-Earth realistic? Is my inverse-square-law-violating furry avatar realistic? Attempts to answer these questions get messy quickly.
What I want to introduce is the idea of realism as a direction. You are realistic to something, not just “realistic” in general. Most of the time, “realistic” means that the thing whose realism we are evaluating, is displaying more or less fidelty to our everyday lives and the world as we experience it through fragile bodies and imperfect senses. So far, so good. But when we inhabit furry avatars and personas and masks, that isn’t and can’t be what it means. We are being realistic to something else.
People are being realistic to their own desires. In the case of the furry subculture’s collective sex life, that’s realistic to their erotic desires. I argue that if you use this as your lens of “realism,” you can spare yourself a great deal of tsuris. It is generally not necessary to decide whether one dragon is more realistic than another and in the cases where it is, you should be making the determination with a skill that everyone should be practicing: the ability to detect sincerity.
If you want to see this kind of realism in a different context, I recommend reading The Metabarons and considering how it is realistic to its creator’s (batshit insane and very enjoyable) vision. It is a great example of the sci-fi writers' dictum that you get one free break from reality-as-we-know it and everything else must follow.
It won’t make you happy to judge creative work by its fidelity to everyday life you experience walking around when the creation of it gave no attention to that fidelity. It may say things about everyday life that you want to engage with, but resist the urge to say that its relationship to everyday life is the only thing that it can be realistic to. There are plenty of flaws that a thing may have while still being faithful to itself (self-indulgent, dopey, insipid — it is all too easy to be these things too while still being realistic to one’s desires).
You should especially not fall into that realism-trap if you’re actively participating in such creative works—that is to say, you’re publishing them on FurAffinity or Weasyl or participating in collective creation on Tapestries, Shangri-La, and such. In those areas, you should definitely prioritize being faithful to people’s desires and fantasies, because that’s the raison d'être of those places: being realistic to people’s erotic desires. The trap is a tempting one: resist it.