Instead of throwing barbs at one another, let's talk more about the nature of revenge and what purpose it serves in society. And as I pointed, when it's seen as revenge and when it is not.
Ahem.
Good idea.
I see revenge as being personally motivated, a way of inflicting humiliation, defeat or harm upon another person. It's essence is payback.
"Your hurt me so I will hurt you", biblical "eye for an eye". If you are wronged there is an unbalancing, a retaliatory action returns the balance to one of equality. Wrong+Wrong=Right. Or does it?
What's the intent and the purpose behind the action?
Do you genuinely believe that person will be shown the error of their ways by having some similar error deliberately inflicted upon them?
Will they come down with a severe case of empathy, think about what caused the situation, review it logically and come to the conclusion that their original action both merited and deserved some form of punishment?
Probably not.
But, will they be less likely to do something like that again?
Maybe. But why?
Perhaps from fear of being punished in the same way again, in which case the prospect of the same happening again would act as a deterrent and revenge would therefore serve a purpose.
But it's not generally seen like that. The intent behind revenge is to gain personal satisfaction from causing misery to the person who wronged you so that they experience a modicum of what you, yourself felt. There doesn't tend to be an intent of changing that person, through the use of revenge, into someone better.
Intent, motivation and purpose change when something is revenge and when something isn't. Maybe it's not quite so vengeance if no one gains satisfaction from it? Doing something because it needs to be done for the good of all instead of for the good of self. Then it's acceptable justice.