He didn't destroy anything, he simply changed the sign in a non-destructive way.
To change the sign, he used stones and rope and erected the fabric as though he was hoisting sails.
Anyways, to most sane people, using the death penalty against "vandals" is an overreaction.
Have you ever suffered any vandalism? I have been subjected to three major incidents, with monetary damages approximating $10,000. Most was covered by insurance, but the cost to me was real (deductibles plus increased insurance cost).
My (and others') damages have cost insureds a lot of money. If someone tried to steal $10,000 from you, would you feel justified in defending your property, perhaps killing the thief?
Is there a difference to you between someone stealing and destroying your property? If so, why?