You are not always going to be able to thrust yourself between your son and the jerks in the world.
If you do it for the rest of his youth what will happen when he's an adult?
The world is full of jerks and dealing with them is a life lesson.
Really, this is nowhere near as horrible a situation as your son is likely to face during the rest of his life.
Better you counsel him on how to deal with jerks then try to save him from them all.