Well, in my own knowledge, there isn't a MMO social game out on the internet that allows users to be humans and has roleplaying as their main goal (unless you want to count Second Life, IMVU, etc but they're more for chatting and dressing up game *Bleh*..) What we make out of the game can be anything despite what avatars we're given. If no one is to complain about Slenderman, anime characters, vampires, werewolves, why complain about a human rp? It is seemingly new and fresh unlike the multiple Warriors rps out there and can bring in some depth and amazing presets (but this is my imagination speaking for itself.) Let people be what they want to be.
@StereoKitty: I'm not sure if you were asking a rhetorical question regarding why roleplaying as a human enjoyable is but to answer that, here you go. Unlike how most people roleplay as animals to be three dimensional, that isn't a normal animal complex, it's a human. Allow me to elaborate, humans are capable of have complicated and meaningful thoughts that actually makes sense. However, the majority of roleplayers apply this sort of mind into animals and discarding their own kind.
I am in no way trying to argue anything here but that is why humans are enjoyable, the emotions they can range yet still be realistic because we are capable of it. It's no difference when roleplayers applies this formula of thought onto animals because it is makes it seem that the characters are humans covered with animal skin.