Agree that no one wants to get shot with a 22, but the whole idea of a concealed weapon in a deadly force encounter is to stop the aggression as quickly as possible. A 22 simply will not reliably cause enough damage to do that. It will cause enough damage to kill, but will take time to accomplish this. A larger bullet will create more of a wound channel, and cause more shock to the system, causing a quicker incapacitation.

Would you use a 22 to hunt deer? Ethical hunters would not because it will not reliably drop the game quickly. Just saying.