I do not correlate the problem bears with no hunting zones.
I correlate them with the hordes and hordes of people
I suspect it's a bit of both, but have no data --- just gut feel. They're pretty smart and (where it counts) social animals, so I expect that their behavior is impacted by us hunting them! Certainly your example of them getting out of control where their territory overlaps population centers (outside of National Parks) is a big (perhaps indeed the dominant) factor too.
"And the stats on the Yosemite website are wrong - would you self report a bear incident if you knew there was a potential that you would pay $5000 fine?"
I expect it's rare, but in fact I do know of one such case. A girl who thru-hiked when I did was breaking the rules by sleeping with her food. She woke to a bear asking her for her food fairly politely, and then a bit more aggessively when she demurred (the bear put its paw on her thigh, she said it became very clear that she was going to have to give up her food). Talking to her about this at Tuolumne Meadows she said she had (or perhaps was about to) call and report it via a pay phone --- she felt responsible to report it, but wasn't inclined to be fined. So it can happen, but I agree with you; I suspect that at least some rule breakers care less or are just more oblivious to the results of bears getting their food. While I didn't agree with her choice of how to (not) protect her food, at least she was going to make sure the authorities knew what had happened.
Hmm, as pay phones continue to get more rare on the ground, I wonder how significant it is that well meaning people won't be able to anonymously report various things in future?