It's certainly true that all caliber pistols have killed people many times over,and that's not even debatable.
However,the intent of the legally armed carrier should be to end a potentially deadly confrontation immediately by causing the "bad guy" to cease his hostile and aggressive actions.
Service calibers accomplish this best. Many years ago Jeff Cooper stated,and I quote:"Placement takes precedence over power." This statement might easily be misinterpreted to mean that small calibers are just as good as large calibers if your placement is perfect. That could even be true in some instances, but in all my years I have never seen anyone who could get perfect placement of their shots under an adrenaline filled moment every time. It just doesn't happen that way.
This is where the service caliber sidearm improves the odds for good guys.With modern performing,well designed bullets,the edge is definetely there. There are many of these loads available that perform with excellance from short barrelled handguns,giving on target results that are hardly descernable from the same load fired from a service size handgun. That is an advantage. You can up your odds of winning also by learning to hit fast without the use of sights
within 7 to 10 yards.
Having the skill to do this is well within the abilities of anyone with normal mobility,but one needs to train in this aspect of shooting in order to be proficiant at it.
Once again,the service calibers are best used for serious defense. It's been shown time and again in the last 15 years or so that with modern well designed ammunition the 9mm,.40S&W,and 45 ACP all achieve about the same result with well placed hits. This cannot be said for the smaller calibers.You're most likely to get not enough penetration with the small hollowpoints or not enough expansion to destroy enough tissue or vital organs fast enough to shut that individual down as rapidly as needed.
If you need to shoot someone,you need to stop him(or her)NOW. I prefer 9mm as I have seen first hand the results of shootings with several types of modern ammo,it carries more boolits,and is cheaper and easier to train with. I love the .45 too,it makes nice large holes,but I prefer more rounds on board.
You pays your money and you takes your choice.The human body is at once both fragile AND resilient,and handguns are all puny.period. Why not stack the odds in your favor?
And,anyone worth shooting is worth firing a burst into. They make the choice themselves.