Most states have a clause in their self-defense laws in regard to "disparity of force" that allows a legally armed person (some states allow an illegally armed person), to use a weapon if they are attacked by a number of people even if they are not carrying weapons.
All the person has to do is reasonably fear for their life. Well, if twenty people run up to your vehicle and attempt to drag you outside, then exercising your rights is totally legal. (In other words, shoot five, the rest will run like hell, or pull out their own weapons.) You can easily consider it a carjacking, and if one of those thugs is armed, then it can be a Federal offense.
I would have NO problem shooting a few of those bast*ards since it will be doing society a favor. These people in this video, in my opinion, have no right to live.