Do that and you're suddenly no better than the Libs. Revenge has a funny way of turning into karma.
Lets ponder that a bit deeper:
Karma is a two way street. I think we can all agree there. So if the left does X and receives nothing bad in return, then they would be immune from Karma. No one is immune.
But Karma is 'what comes around, goes around". Like a boomerang. So their sins have to be revisited on them. They arent going to do it to themselves obviously, so the only people left to fulfill Karma is the people they visited those sins on. And if we don't, then they would be immune as shown above.
So we are bound by Karma to fulfill our obligation, balance the scales and with scales balanced, there is no Karma coming back on us..