It's probably just Apple layers avoiding getting involved in any copyright lawsuit over the copyrightability of weights, by avoiding licensing it except under what's clearly fair use anyway, making copyrightability moot.
Yes this seems more about protecting them from a lawsuit. I don’t think they actually give a shit about the weights or they wouldn’t release them at all. I suspect they just know they’re training dataset isn’t perfectly “clean” and don’t want to accept any more liability than they already have.
