Robbers starts shooting in restuarant, one is killed by CCW customer.

[GreenStormCloud]

29. A few corrections for you.

Most criminals with guns don't want to kill. They want your money, or your iPhone, or your credit card, or that Glock they caught sight of under your sweater.
Each situation must be judged by itself. In this one, the bad guys opened fire, shooting the owner, as soon as they came in the door. That clearly established that they were in a killing mood, and that everyone's life was in real danger. You seem to have difficulty understanding that the criminals started the shooting.

Most aren't trained. They're probably afraid of their own weapons (that's a surmise). They may be wired on meth. Which makes them extremely dangerous, more likely to do something really stupid. If they do kill someone, they've nothing more to lose by killing everyone. Why leave a witness?

And in such a situation you want innocent civilians to rely on the tender mercies of thugs who have already used deadly force on someone? How many people must be shot before you graciously give a citizen permission to fight for his life?

Fire fights in restaurants? Movie theaters? Schools? Parking lots? Freeways?
Or churches, stores, etc. Anywere a thug places you in deadly danger.

The temptation to pull on a bad guy aiming a gun at someone else is enormous. Be a hero. Save the day.
Not merely aiming - SHOOTING. You are having great difficulty in understanding that the thugs had already opened fire. When the thugs have already started shooting, your own life is in danger.

And that guy in Detroit, pulling on two armed bad guys, one holding a shotgun?

Not smart.

Yeah. He killed one bad guy. And got some pellets before the shotgun dude fled.

He had no choice. The bad guys had already started shooting. Do you think he should have sat passively and waited to be shot in turn? Once the bad guys start shooting, all bets are off. It is then time to fight for your life.

But it could have gone another way, had the man with the shotgun used it to blow the place and everyone inside into smithereens.

Could have, but it didn't. Thugs almost always run away when bullets start coming their way. It is extremely rare that they stand and fight.

You are confusing self-defense with agression.