Oh I have no doubt that someone will eventually die from a 22lr/mag shot, but defending yourself isn't about killing. Defending yourself is all about stopping the threat as soon as possible. A 22 under most circumstances will not quickly and cleanly stop a full grown man.
MOST (not all) gunshot victims that die do it four days after the shooting. I'm not disagreeing that bigger won't stop 'em better.
If my choice is carrying a P22 or being an unarmed peasant . . . Not too difficult a decision.