Anyone condoning the .22LR as a defensive round because of it's killing power is starting out with a false premise.
Not me--I'm saying that .22 LR has nearly the same "stopping power" as the service calibers, which in physical terms is practically nothing unless you hit something vital, and in psychological terms it's even closer, as any sort of gun at all is pretty intimidating to those who do not wish to die.
The killing effectiveness of the .22LR, or how many people a coroner, doctor EMT, etc. say have been killed by a .22LR, or the fact that a 9mm, .40S&W, .45ACP etc. won't kill any deader than a .22LR doesn't mean squat because in a self defense situation the goal is NOT to kill the attacker. The goal is to stop the attacker from continuing his attack as efficiently as possible so that you may continue to live a happy, carefree life and die of old age.
So how do the larger calibers stop more effectively, aside from the obvious, such as being slightly more likely to hit something vital, and causing faster bleeding? With regard to the latter, the difference is still not enough in the vast majority of cases to prevent the attacker from inflicting a lethal wound on you, as it will likely take minutes to affect a stop.
Once you realize your goal is to stop the attack as efficiently as possible, if you know anything at all about terminal ballistics (even if you know nothing about it you can easily see with your own eyes how enormous even a 9mm is in comparison to a .22LR)
The difference in size between .22 LR and 9mm only tells me that it is slightly more likely to hit something vital. Several times larger than small is still small in comparison to the size of the target, after all.
you come to the logical conclusion that a standard defensive caliber is way more efficient than a .22LR in accomplishing that goal.
The conclusion you're jumping to may be logical, but simply being logical does not mean that something is true, as there can be false assumptions as well as failing to include enough factors that reflect physical reality. For example, one might conclude that because 9mm JHPs are more effective on humans than 9mm FMJs, then the same must be true for even larger creatures. Is that not logical? It is indeed, however it may well be false nonetheless because 9mm JHPs may severely underpenetrate larger creatures, failing to even reach vital tissues, while 9mm FMJs may penetrate enough to be far more effective. What might not seem logical at first on the surface could very well be true regardless, once all of the necessary factors are taken into account.
While we're on the subject, the same principle applies to the vaunted .22 LR CCI Stinger because of its impressively explosive effect on small animals, but I consider it a poor choice for defensive purposes against humans because it will likely be short on penetration, whereas the CCI Velocitor, which is not nearly as impressive on gophers, should be far more effective on humans. This is also a reminder that load selection can sometimes be more important than caliber (some folks might say that this defies logic, too, but it's still true).
Is a .22LR better than nothing? Obviously it is, it would be foolish to argue otherwise. But to say that it's even remotely as efficient at stopping an attack is absurd.
With the right loads (e.g. CCI Velocitor) and sufficient barrel length (3" as a bare minimum, which is reasonable), a .22 LR handgun can launch bullets that penetrate flesh just as deeply as those of larger calibers (JHPs in 9mm and larger), which in my view makes them better than remotely as efficient, and I don't think that this is absurd in the least. Like all logic, mine is based on certain assumptions, which in this case is primarily the significance of shot placement and penetration being above that of other factors--not to the exclusion of the latter, as I shoot .40 S&W myself for a number of reasons, but they are the most important factors. The best way to disprove my conclusions would be to discredit my assumptions.
A thug might be deterred more by a harsh word of warning backed by a .22 handgun, than by just a harsh word of warning, but the defender would have to project the intent to follow through and be prepared to shoot multiple times to stop if necessary. And a .22 will kill even if it might not be a one shot stop weapon.
I hate to paraphrase a guy like Stalin, but he was correct when he said that quantity has a quality of its own. I don't really believe in one-shot stops with the service calibers, either, and if .22 LR makes it possible for beginners and those who are sensitive to recoil to place more accurate shots on target quickly, then I would say this makes them more effective shooters than if they used a larger caliber. I use a larger caliber because I can, not because it's SO much more effective than .22 LR, because it is not. When my life is on the line, I'll take any edge that I can get, and if .22 LR gave me an edge because it's all I can truly handle, then I'd use it instead.