Two of those three incidents required multiple shots to subdue the bear, with the three shots in the third incident described by the shooter as being a "lucky shot".
In my encounter with a bear at a work camp, the man with the hunting rifle needed one shot to cripple the bear, and a second shot to quickly put it out of its misery. And luckily, he had time to properly set up the shot.
While this might sound very Stephen Colbert-ish, bears are vicious wild animals. They will maul you to death with great efficiency if given half the chance, with polar bears being the most aggressive of the lot.
Now with that in mind, it's doubtful you'll ever encounter a bear in a big city unless it's at the zoo in a protective enclosure. So the possession or use of a firearm in heavily populated area by the general public is extremely difficult to justify.--
Watch my future television channel's public test broadcast!