When people mention arming themselves, they are thinking about it, but not to the final “conclusion”.
Guns make untrained people feel “strong and invincible”.
Jip, as parents one is more “dangerous”. Keep in mind that @calypso used stats in a military conflict situation, and a rather large percentage was still not able to act.
Taking that to a civilian untrained level, a lot of bad decisions are going to ruin a lot of lives, decisions taken due to inexperience with the consequences of one’s untrained action.
Yeah, I have thought about this a wee bit … just bad to much worse conclusions. Hence my reaction when people say "I have a gun and lots of bullets … " and other variations of that. People who fully understand the situation would never say things along those lines.
Avoiding deadly conflict at all costs is a good motto, to begin with.
Run as fast as you can until you have absolutely no cards left to play with.
Then only act with a deep understanding of what is coming next.
EDIT:
Wife and daughter went to a self-defense class. The trainer asked who has a gun in her handbag. One lady indicated she had. He swapped it with a training “gun”. Back in her bag. He stood 10m away, told her he is coming for her, she must get the gun out, and “stop” him.
He walked, yes walked closer (fast) shouting and screaming at her … she never even got her purse open. She was so rattled.
Try that with a trained person who knows to keep the gun loaded at all times, just the safety on … and not in a handbag either. 
EDIT 2:
Our son’s career choice is a stuntman. He trains and trains how to pull and “use” a weapon, yes, it is for movies, but the trainers are the real deal. Over and over he trains till he gets it right.