Hello Kitty not a cat, has never been: Sanrio
I find it bizarre the way this concept has been stretched and pretzeled the last couple of days. It's not a difficult concept to understand, but I suppose that's what the Internet is for these days-- discovering some idea that should have been obvious all along and then acting incredulous about it.
All Sanrio is saying is Kitty is not a cat in the sense that Mickey is not a mouse and Goofy is not a dog. They wear these familiar animal shapes not because they're animals, but because animal shapes are appealing, the visual vocabulary of cute cartoony works. Kitty is an anthropomorphic character and we've had those for as long as we've had pop culture. Way back when I was a kid, thousands of years before your grandparents were even introduced via OK Cupid, Aesop did this kind of thing all the time, using animals to illustrate human foibles. I don't remember any of us running around screaming, "Oh my god, a lazy cricket and an industrious ant! A fox who sneers at the grapes he can't reach! I've been lied to!" Eventually, our animal-shaped avatars began wearing clothes and selling merchandise but they've always been us.
Ultimately, what Kitty is... is her own unique self.
A good friend of mine was Sanrio's North American web designer for years so this is big news for her, but only because she also doesn't get the furor over something that should have been obvious all along and really isn't difficult to understand at all. Still, I'm pretty sure she's happy so many people are talking about Hello Kitty.