I have seen videos of the Inuit indians using a 22 LR on polar bears and getting the bear. They do use them there, check up on it.
I saw a documentary (Gordon Eastman, I think) of Native Alaskans coming up behind a swimming Brown Bear, in a canoe and carefully placing the shot behind or IN the ear with a .22 rifle from a distance of 2 or 3 ft. That's not bear defense.
Didn't see the video you refer to, but I suspect they shot the bear while it was swimming and helpless, since it isn't likely that the Intuits have survived so long by being suicidal or stupid.
Whatever the circumstances (that you havn't elected to tell us about), the conditions were obviously ideal and represented minimal danger to the hunters, who, if on land, were most likely backed up by a real rifle.
Saw an Alaska State Trooper episode where an inhabitant of a northern village was on "Polar Bear" guard duty armed with a Mini-14.