I deliberately put the term "go nuts" in quotes because it isn't exactly accurate -- as you said, many of these attacks have simply not been explained. I was always under the impression that an "unexplained" bear attack is more likely to involve a black bear than a grizzly bear for some reason. A Canadian female cross-country skier was killed in one such attack a couple of years ago while training in the summertime in Quebec, and as far as I know nobody has ever figured out exactly what that attack was all about.
Here's my beef with bear. The biggest problem with bear is when the moose calve in may/june. Bear take 85% of moose calves; pretty tough on the resource. When there's no calve survival, the average age of moose population gets older until all yu have is barren cows; and then the moose just die out. Both grizz & blk take the calves. I think everyone around here has seen bear pullin down calves at one time or another.
Up until about 30 years ago, there was sensible predator control from the air & the bounty system. The new balance of nature approach is just what it is; boom and bust; the land supports 10% of the moose it is capable of. That eventually means no hunting for humans who also subsist off the land. I hear down in Canada that they have the same probs but just close hunting down; prefer feeding increased bear & wolve populations rather than humans. The politicals are beginning to address the predator problem up here; long time over due as we have way too many bear and in places wolves.