I understand the sentiment and reasoning regarding a temporary disablement of a bear with pepper spray VS killing the animal.
My point is simple, however, If the pepper spray does not deter the bear you WILL be lunch. I have a close friend that survived a bear attack on the Alaska Peninsula while moose hunting. The bear (a very large male brown bear - over 48" high at the shoulder while lying down flat on the ground) was in tag alders and bolted at their approach, circles until it hit their back trail, and came straight up the back trail at full speed. It died about 12 feet from where they were standing.
The provocation was, apparently, that they were in the same neighborhood as the bear. They were not stalking the bear, and had no idea that it was there until it bolted, then turned and charged.
My friend is a very seasoned outdoorsman, and he was with a experienced, professional guide. This kind of thing is not common, but it happens every year in Alaska, and people are killed in Canada and the rocky Mountain states often enough to provoke these discussions.
I am proficient with firearms and usually have some form of protection with me when traveling. The only times I have drawn a weapon is in encounters with two legged predators. I much prefer to never have an experience like my friend's, nor do I go looking for trouble. I don't even kill rattlesnakes unless one of my dogs is in danger of being bitten. Still, I stand by my statement that, in the most extreme instance, a firearm can save your (or another's) life.