No criticism of Professor Smith, but one would think this is so obvious as to not need saying.
There are multitudes of people, many of them hunters, who will say that bear spray is so much better at stopping bears, that bear spray should have been used.
It is all based on fake science.
http://gunwatch.blogspot.com/2014/10/wybear-spray-v-bullets-flaws-in-studies.html
Also, while your article correctly addresses selection bias, it's the media's selection, not the bears. Most charges are bluffs and will stop at 20 (too close) to 30 years. If I spray a bear at 30 yards, and he stops, the overwhelming likelihood is that it was a bluff, the bears selection. Though chalked up as a successful spray. In my unprofessional opinion, which a few experienced with bears have agreed, if it's a true charge, the bear is coming through the spray. 30 yards, that's 3 seconds. Or less. If you're not ready to shoot, it's too late.