Good luck winning that one in court.
The only time violence is acceptable is to protect your person or property. If a person is standing between me and my car, I am not allowed to initiate violence or even threaten violence. If I have a reasonable suspicion that I will be attacked, then I can act to defend myself.
If they are simply blocking access to my vehicle, my responsibility is to report the offending behavior to police, and let them take care of it. Anything beyond that is likely to find you in a jail cell until you have an opportunity to explain it to the judge.