No one, myself included, would recommend a .22 caliber handgun as the ideal defensive weapon. For that matter, I wouldn’t recommend any handgun at all as the ideal defensive weapon. We carry handguns because most of us find it a tad inconvenient to carry a tactical shotgun, or main battle rifle as we go about our daily lives, and most folks tend to get a little upset when you get on the bus with one. If I knew a fight was coming my way, my preference would be a crew-served weapon, preferably with the ‘crew’ in tow. So, a handgun, any handgun is at best a compromise. But then, we’ve all been around long enough to understand that life is a never ending series of tradeoffs.
I will not debate the .22 vs. 'whatever' for self defense. If, by choice or circumstance, your only viable option should happen to be the .22 rimfire, so be it. I have no problem with my students who choose the .22 for self defense, regardless of the reasons. They all know that I advocate using the largest round you can handle easily, afford to practice with, and shoot well. But, we do not live in a perfect world.