Here's the problem with pulling a gun on rioters/looters.
Unless you are legally justified in using force, the law will not be on your side. You may survive the moment, but the criminal justice system has all the time in the world to identify you, track you down, and prosecute you. Remember the media is against you, the online mob is against you, and half of the political spectrum is against you.
We are not at the "weapons free" stage where law and order supports what needs to be done in a morally and historically justified sense. We are still held to account under self-defense/justifiable homicide laws for a peaceful society, not one of open civil warfare. There are severe repercussions for taking measures a soldier would deem prudent in combat.
The mob can get away with what it wants because there is little political will in most areas to aggressively arrest and prosecute the perpetrators. They also have numbers on their side making it difficult for police to apprehend the sheer volume of criminals and also sympathetic people in the mob will resist/attack arresting officers.
Armed citizens can't get away with stuff like that. As a whole, we hold our fire until we absolutely can't take it anymore. We have an amazing tolerance. A lot of this is rooted in the fear of being prosecuted or being alone with the crowd.
If a man starts shooting, he has to be prepared for the possibility that the crowd goes against him in a mad rush to grab the weapon. Others in the crowd might also be armed. When it comes to the use of force in this situation, the use of force (beyond being justified) has to be enough to deter the crowd. Are you able to put out the volume of fire to defeat the crowd? Can you sustain it? Can you show enough force that not just the weak weenies run off, but the bad guys too? And can you maintain that force to keep determined bad guys from coming back?
What if you are arrested and all your guns are confiscated? What then? Police can't/won't protect him from any retailtory violence even he is in the right. He will constantly have to be on guard for someone who may wish to burn him out, etc.
Just imagine how much worse this could get if guns are banned and radical leftists are in control (more than now) of the judicial systems?