I do not care whether or not it would deter others from doing what he had done. In short, at heart, I am just like the condemned criminal when you get right down to it. Whatever his motives or excuses for committing the crime, mine for seeking vengeance would be just as compelling, just as bloodthirsty. You see, for better or worse, we have chosen to adopt a standard of abstract justice which hopefully controls the all too human instincts of both the criminals and the victims. We are, after all, carnivores.
Carnivorous animals kill for a living.
And, we like killing. It gives us a thrill to draw the blood of our victims. This is WHY we do it out of sight. To hide this dirty secret. Like many other aspects of killing and dying, we hide the details from each other hoping to suppress and control the impulses.