Well, I think he didn't like a non-charging spot being taken up by an electric car to be used to charge the car.
Look, anyone who's unplugging someone's car without their permission is a bit odd anyway.
For a little while I was secretly hoping he was going to cut the charging wire with a set of bolt cutters and fry himself. May the good lord forgive me for harboring such thoughts.
Forgive me people for continuing to refer to this person as a 'him', although I still bet dollars to donuts it is a male.
Women are generally not wired this way.