this happened in california which is not a CC friendly state and not a stand your ground state. any civilian caught shooting would probably be arrested whether or not in self defense and charged. i would just guess that it would probably be viewed as an escalation of violence since none of the protestors seemed to be carrying. imho pepper spray, mace, cane, or similar might be useful.
Sounds like an opportunity for "Raid". They should look into packaging their product in pocket sized cans. Could pick up a 6 pack for the family rally outing.
You really wouldn’t have to shoot though, just showing a gun is enough of punk repellant but if you were caught they’d probably throw the book at you like they do here in New York which I belive you face 5 years in jail even if the gun is licensed from another state which is outrageous for a constitutional right. All the time we got people here who are thrown in jail for defending their life with a gun whether they shoot or not. Probably the most infamous being the Bernard Goetz case where he shot 5 muggers on the subway (they all lived unfortunately) Not only did he go to jail, he was incredibly outrageously sued by one of the muggers who was awarded $41 million which Goetz still owes to this day.