I think people tend to get somewhat fired up (as we say in Arkansas) when it comes to self-protection. Here's a good resource on bear attacks with real statistics:
"In the last 100 years, 57 people have been killed by black bears in North America
. The same number of people die of bee stings in the United States every year."
I did some checking and a large number of those deaths were in Canada.
We all know there have been some legitimate attacks in the Smokies/Cherokee NF in the last ten years or so. But I think we can also all agree that most if not all of those attacks were provoked by stupid human behavior, usually related to feeding bears and letting children approach bears. That can have tragic consequences.
Here's the relevant federal statute relating to discharge of handguns in the Smokies:
"All hunting or the killing, wounding, or capturing at any time of any wild bird or animal, except dangerous animals when it is necessary to prevent them from destroying human lives or inflicting personal injury, is prohibited within the limits of said park [i.e. both Great Smoky Mountains and Shenandoah National Parks]."
16 U.S.C.A. § 403c-3.
In other words, the law allows you to use a weapon in legitimate self defense. That said, I promise that the National Parks Service would look pretty closely at whether there really was a necessity to 'prevent [bears] from destroying human lives or inflicting personal injury.' No one wants to see the bears shot at when they simply show natural interest in people. Moreover, not all the national parks have the same laws: Yellowstone is also opening up to concealed carry but there's apparently no self-protection excuse for discharging a firearm there.
I would just encourage everyone contemplating carrying a gun in the park for 'bear protection' to ask themselves what they would do if they didn't have the gun. If there's an option that does not involve shooting the bear, please take it. You'll save the bear and probably save yourself a lot of hassle to boot.
You do not want to have to cough up the money to 'defend yourself' from a criminal prosecution, either, believe me.