AFAIK, man-eating tigers that actually approach human settlements are usually old/injured/sick, an d cannot hunt normal prey easily anymore. They get desperately hungry, and, while they normally will avoid human settlements, eventually they get so hungry that they approach and eat a person.
The wiki on it is good reading.
The bear has reasons for killing, and so do we.
This aversion to seeing people as part of the food chain is beyond me. We have a life which we want to live – and man is curious and adventurous by nature – and when bears taste human flesh, they become a greater threat to humans. So, we, being the ultimate tool maker (thanks evolution), put those tools to use.
I don’t deny the bears have tendencies and areas they frequent, but don’t deny that humans explore, study… and, well, act human. We get around. If bears eat us and become more dangerous because they see us as prey… then we rise to the top of the food chain.
Much of Denali Park is open terrain with scrub brush which is thick enough in many areas to conceal a bear. 50 yards is far too close in any conditions, as a bear can cover that distance before you can react. While this man was an experienced camper and hiker, his failure to move away from the area immediately was fatal for him. Bear’s are usually killed because they are sitting on their food cache and will defend it against all comers. Also, when a bear decides that humans are easy prey and a quick lunch, it’s a death sentence for it.
Yeah, the Superintendent of the Park said that they put the grizzly down because it killed the stupid hiker, dragged the body 150 yards into the woods, ate it, and sat on it, defending it against predators. If it had just mauled him and then fled, they usually don’t put them down.
I thought on of the bears charged the Rangers.
Typical quoted top speed for a bear is 35 mph. Once up to that speed, the bear would cover 50 yards in 3 seconds - definitely quick, but a lot longer than normal human reaction time.
Hunters harvest about 2,000 of the estimated 30,000 Brown Bears in Alaska every year. I can’t think of a good reason to not kill the bear.
While we’re on the topic, do you know how to tell brown bear scat from black bear scat?
The brown bear scat has little bells in it and smells like pepper.
Bazinga!
And since the comedy club has been opened, I just want to say that I always wear tennis shoes in bear country. Invariably, someone in my party will point out that a human can’t outrun a bear. My reply, “I don’t have to outrun the bear, I only have to outrun you.” 
Yeah, you’d have enough time to turn around and almost take two steps. Weapons are not allowed in the park.
How about bear-deterrent spray?
I know a lot of hikers - even very liberal ones - that conceal carry when on the trail and especially so in brown bear country. Typically they’re not permitted, but they do it illegally anyway. It’s quite the issue in the hiker community.
I believe they’ve allowed guns for the past few years.
I encountered a bear in 2004 on the High Sierra Trail in Sequoia NP:
http://www.tmk.com/transient/6F5S3305-m.jpg *
After going well out of my way to locate a ranger and notify them (the paperwork says “Report all bear sightings to a ranger” in quite a few places), I was told “We know about it, it’s been up around Crescent Meadow for a couple of days”.
Apparently they don’t post notices or close the area as that would encourage people to try to see the bear. Of course, that doesn’t help the people (like me) who happened to be there anyway and met the bear by surprise.
Looks like you’re right. Even so, a charging grizzly is going to be tough to kill, even with a large caliber handgun. Or even hit, in the few seconds the guy would have had, for that matter. I would bet he was unarmed, and probably just had either bear spray, which is fairly ineffective against grizzlies, or was wearing bells, which do nothing other than announce where dinner can be found.
The Treadwell bear was taken down with a large caliber pistol and two shotguns.
NPR had an interview with the park superintendent where he goes into detail about the circumstances surrounding this particular bear’s behaviour and how it was determined to be a threat.
Emphasis on the word “shotguns”. Even large caliber pistols are fairly useless against a charging bear.
People are delicious. You can’t eat just one.
That’s not how bears work. They want to avoid you. Also, you may not kill a charging bear with a 9mm, .45, or even .357 and .44mag, but you’ll very likely scare them off with just the gunshot sound. Wounded predators don’t fight to the death either, unless cornered.
