A lot of good it would have done in this case.
I think a lot of people get confused about the difference between a National Forest and National Park. The incident in this story took place in a National Forest where it is perfectly legal to carry a loaded handgun. In a National Park however, you weapon must be unloaded and disassembled.
That's been my frustration on this thread too. Not only can you be armed in national forest, but they have (usually) open hunting seasons on these kinds of lands, and while carrying of rifles is restricted to hunting seasons, carrying a pistol for protection is not, any more than it is anywhere else, according to state law.