^^^Ok... I'll have this discussion. I rather enjoy the topic. I only say this for the safety of you and anyone you may be protecting.
I say your wrong. That could possible be the least thought out reasoning I have ever seen for justification of the carrying of a .22 caliber handgun. Plain and simple I think you are better off NOT carrying at all then carrying a .22 handgun. To me it may lead you to think differently about a situation should a self defense issue arise. If you have a gun, your defense mechanism might be different then if you did not. With a .22 you should be thinking about turning and running, not staying and fighting.
First of all the accuracy of your shots, on your best day at the range (against a non moving paper target) would be diminished by 50% by the stress of the situation at hand. If you have taken any training at all, you are taught to shoot "center mass" for a reason. Its the biggest area. Relying on the fact that you can make well placed head shots is preposterous. The stresses of a defensive shooting removes your finer motor skills making it extremely difficult to hit "center mass" much less a head-shot. I just dont see the typical person being able to hit a large charging threat in the head. These shots will most likely be taken under less than perfect lighting conditions, and you may be getting shot at yourself. Simply put, if your defensive plan depends on a perfectly placed shot to the head you need a new plan.
Also the caliber is absolutely inadequate. I could go on to also add: .25, .32, and .380, all of which I do not recommend anyone carry as a self defense round. Small calibers simply do not possess the ballistic properties required to ensure an incapacitating wound, even despite near perfect shot placement. And I will again reiterate that those shots are nearly impossible to obtain while under the stresses of a defensive shooting. Will a .380 kill a human size threat? Absolutely, so could a BB gun. But most likely only if you can afford to wait several minutes for your threat to bleed-out. How will your threat spend those minutes while he is bleeding-out? Shooting at you, perhaps? You want to carry a caliber that possesses enough (incapacitating) force to take your threats will to fight away. Im not going to get into the argument that its .45 or nothing, but there are plenty of caliber choices, in a metric shat ton of guns to chose from in a "service caliber".
We carry a gun in preparation to face the last thing we ever want to have to do....shoot to defend our lives. It's only when I'm in absolute grave danger that my weapon becomes the only thing standing between myself and death. Knowing that, why wouldn't I want the absolute best tool available for the job? Your handgun can quite possibly be the only thing that gets you, and your loved ones home safely tonight. With this in mind, I hope you will carry a handgun with more stopping power potential than a .22 caliber has to offer. I want the exact same thing that you want. I want you to make it home safely and if you have to defend your life a service caliber is the better tool for the job.