I think in a place like Denali there must be some ultra strenuous protection of the wildlife. The normal concept of self-defense doesn't work there, because its the bears home, not the hikers, and bears are gonna do what bears do.
Emphasis by AZAK
A bear mauling is a bear mauling is a bear mauling...
It does not matter whether it is in Denali (I have hiked through there and seen bears), or in some other parts of the Alaska Bush (been there too and seen bears), or just outside my living room (guess what... and seen bears)
Self defense is just what it says = self defense.
THIS IS ALASKA. Cut the state in half and Texas is now the third largest state. Forget what Alaska looks like on most maps you have ever seen; no, we are not in the Gulf of Mexico or out in the Pacific next to Hawaii and no we are not about twice as big as Hawaii. Now think, " Alaska is Really, Really Big!" Super-impose Alaska over the lower 48 and our state almost touches the North, South, East and West boundaries of the lower 48. B-I-G.
http://www.birds-eye-view.alaska.edu/ch2/story2-3.htm
Now, think about the people population of the state. Way less than 1 million. Most of your big cities (each) have way more people than our entire state! And about 1/3 of our human population is in one place - Anchorage!
Bears have a Whole Lot of range up here! (And in almost the entire state, no people as even remote neighbors.) There are many bears up here. They are Not an endangered species up here. Life is pretty good for a bear up here. Lots of salmon, berries, moose, and the occasional slow and slower witted tourist; To paraphrase Chad Carpenter, the Alaskan cartoonist: Step outside and Welcome to the food chain. (And you are not at the top.)
Common sense quiz time.
A bear is charging aggressively you:
a) Let nature take it's course (with you as a possible entree)
b) do something to avoid a)
Most of us will probably choose b). Aside from not being there in the first place (moving to Chicago, opps bad example, San Francisco), if you live in Alaska (and I will even include Anchorage for the sake of argument) bear encounters are a possibility of life.
I have advocated bear spray for years, look at the results in Alaska:
http://www.adn.com/2008/04/20/381252/spray-proves-its-worth-in-bear.html
And if you don't want to read it all, or just need the Cliff Notes version:
"And in none of the 83 cases the scientists examined was a bear-spray user seriously injured."
In addition to bear spray, I also carry one or two firearms with me when I venture out; two for the bush, one for "town".
And my closest non-hunting bear encounter ended at about 4 feet. And I didn't care where I was at that second in time (Denali or The White House formal dining room) that bear was Not getting any closer since I had a say in the matter.
YMMV
I also buckle my seatbelt, much higher likelihood of hitting a moose than getting mauled by a bear.