Partially, although he's not the only one to look at it. I was kind of averaging out.
As has been said - it's hard to look at it apples to apples. A guy with a gun on a sling may not get the gun into play in time - whereas a guy with spray did. Does that make the gun 'less effective'? Depends how you look at it.
Furthermore, most of these studies look at 'gun' as if there is only one gun in the world. Someone takes a poke at a griz with an sks, or a shotgun with bird or buck shot, and that's supposed to compare with a guy using a 45-70 or a slug, as if they were the same thing?
To do a truly effective study, you'd have to dig a lot deeper and break things down a little more. Spray is a single mostly homogenous product - a bottle i buy is likley to be the same more or less as a bottle you buy. Firearms are anything BUT homogenous. Vastly different cartridgs, different actions, different aiming systems, carrying styles which affects how the gun is brought into play, not to mention as you say proficiency issues which are even more of a factor with guns.. etc etc etc.
I have little doubt that a man who is proficient and knows what he is doing with a shotgun loaded with slugs who is ready for the bear when it charges is just going to ruin that bruin's day, even if it's a big'un, more often than not.
And really , the point wasn't that spray is MORE effective than guns, but rather that clearly it's effective when used right, and therefore should be considered as part of any bear defense stratagy where appropriate.
