I suppose that could be because I am wrong. That big white bear is not listed anymore, if it ever was, which . . . . sorry . Still, exotic materials can be a problem, for example, there are a number of seals listed. ahhh forget it. never mind.
There are ways to work around the rules, just ask any republican. I think Polar bear can be sold if it was skinned before the protective thing went into effect. But you are right, there are skins that will get you into some real trouble.