In general, the police will not be held negligent if they do not …
In general, the police will not be held negligent if they do not show up in a reasonable amount of time when you call 9-1-1 - so your security is your responsibility. Quick Quiz - who show sup LAST at a crime scene - the victim, the criminal or the police?
In some instances, a deadly weapon is the only alternative - ask a young woman who is facing three men who have already vocalized to her that they are going to gang rape her. Would she rather that she had a cell phone to call police - who can come and take the report after the fact - OR that she had a pistol in her purse to use as an equalizer and level the playing field again?
As I said, I have been carrying for more than a dozen years, and have only had to resort to deadly force twice, both times against dogs. So using that capability is only about 0.1% of the time that you carry. When was the last time you used a spare tire, and how many times in your life? Yet you carry one in every car.
As for the guided training that civilians get, a lot of it came from learning to shoot squirrels and other wildlife as a kid - or soda bottle and cans with a .22 rifle. The real criteria that I would prefer is if they know WHEN to shot and when NOT to shoot. THAT is a more valuable skill - discretion.