Whether it is intended as a joke or not, there are many who think this is an appropriate response. This sort of action needs to be strongly discouraged in my view. I don't take it as a joke, intended or otherwise.
Dan
Why do you think morons do "stupid" things like the OP described? Because they know virtually everyone will cower and do nothing and they know the odds of the police doing anything are virtually nil. First time you get run off the road and hurt, you'll feel differently. Or if some idiot hurts someone dear to you, let's hear that same advice. We all know it's better to turn the other cheek, but it is also important to let others know it is not smart to "screw" with your safety either. The crazies will rule the road if they believe others will do nothing.
My recommendation is to pick your fights CAREFULLY and let discretion be the better part of valor.