This guy deserves a unique punishment such as being tied and gagged on a gurney and having a 200 watt soldering iron planted in his anus. The input voltage would then be ramped up slowly so that it takes no less than two hours to reach its peak temperature.
Human rights end when people don't act human any more. Take the trash to the incinerator, spread the ashes and move on.
Seriously, if he just drove around, kept his mouth shut and avoided a scene nothing would have become of this.
I do NOT understand road rage of any kind at all. It's just plain silly. If someone wants to pass or move over, just let them go. If they cut you off, move away and life goes on. This crap with flashing lights, flipping fingers, yelling, throwing apple pies, etc. is quite silly and dangerous.