I would definitely come to a measured defense of my wife if someone was chewing her out. On the other hand, my wife would not be parked in a handicapped space -- even if the car was tagged appropriately -- unless she or a passenger in the car was significantly handicapped. I say a measured defense for a reason. Words are, generally speaking, no reason to inject force into a situation. My response would have likewise been verbal rather than a use of force.If you were to walk out of the store and see some guy standing there chewing out your wife or girlfriend, how would you have responded? Would you not go into an immediate defend your loved one mode?
This incident went off the rails when a thug used force to make his point. While I don't see anything "right" about the actions of the shooter, particularly when acting in a verbally aggressive manner to initiate this whole confrontation, he appeared to be escalating no further until force was introduced by the now-dead boyfriend. Like so many cases, this incident was preventable by either party. Neither of them, in that moment, acted in a measured manner that might have prevented this loss of life and the aftermath.