Very cynical, and wrong. Revenge is carried out by the victim or someone who is emotionally attached. Justice is an objective third party, punishing based on evidence and an established standard which the offender has knowingly agreed to and broken. (By being a citizen of our country, you have implicitly agreed not to murder, for example, or by signing this contract, you explicitly agreed to complete the work.)

Sure, justice gets twisted on a regular basis. But that doesn't mean it doesn't exist, as a concept, as something different from revenge.