That's not totally accurate--some art dolls are meant to be played with. The difference is that art dolls aren't toys. They aren't meant for children. But there are quite a few art dolls that are interactive (automata, ooak bjds, etc.).
You're welcome. And no, it wasn't a dumb question at all. Art doll artists have trouble coming up with a definitive answer to this one all the time and it's frequently easier to say what it is not than what it is.