What Can You Do If a Mob Surrounds Your Car? (youtube.com)
At this point, the mob is not protesters, but organized crime, an organized attack. Anyone involved is participant. Treat them like the criminals they are, and treat this as the assault it is.
Lethal force is justified if you or someone else is facing imminent threat of death or serious bodily injury, or if a felony is being commited upon your person or in your home. (Most states in US, not all, reportedly.) You can't use lethal force usually to defend only property. A person has to be at risk. If they're trashing your car but probably not you, you can't use deadly force. You legally have to just sit there, basically (I mean you can't just drive through them). You can drive slowly and methodically, posing no risk of harm to anyone. You are ‘retreating’ when you do this, and there is no requirement you retreat in most (but not all) states. If windows are smashed, things change. Now glass is in the car, you already have risks of serious bodily injury or death. The stranger is now invading the space of the car, and it is reasonable to assume they might or will harm the occupants. Driving away more rapidly is now reasonable and could be legally justified in some (but not all) places. If someone reaches into the car to grab you (or pull you out), you area now ABSOLUTELY in imminent threat, plus a felony is ABSOLUTELY being commited upon your person. It is a felony assault, car jacking possibly, robbery possibly. If there are other passengers, you have more than one person ABSOLUTELY in imminent threat.
There should be national education on this. That if you smash someone's car's body, you can be charged only with that, but if you break their window or try to open their door, you are now committing assault and you have escalated this to a deadly threat level. Americans already have something like this with guns. Most or all Americans I have talked to, immediately and strongly recognize the difference between carrying a gun and carrying a gun with the safety off or cocked or drawn (unholstered). There are really different things for them, and they immediately understand the situation is really different. Same with an openly shown gun and a concealed gun.