Admittedly in my haste I mixed National Forest with National Park. However, hunting does exist within National Parks, just not on the same basis. Usually its done by state/federal hunters in a resource management form, not over the counter permit and tag.
As far as State's rights goes, the new law reverts regulation to the state while enforcement remains federal. If the state doesn't want CCW in parks they can create state level regulation specifically or do as California does and not issue permits.
Personally I'd like to see states have full control over the parks, which is where my interests lie, not in trying to convince you that you should or should not carry a gun.