The article title is a little misleading. The hunter didn't claim pistol was better than bear spray for bear defense. In truth:
Losinski said Adams is left-handed and had bear pepper spray on his left side, but couldn’t get to it during the attack. Losinski said Adams with his right hand was able to reach his handgun on his right side and fire shots that Adams told officials he thought struck the bear.
It appears to me that the hunter had planned on using the bear spray as his first defense, because he put it on his strong side. The pistol was the backup. In this case, he used the backup. Isn't there a saying: two is one, and one is none? I'm glad it worked out.