So long as humans are being tried and put up for justice, humans administer justice, humans define justice, and/or humans exist, I can guarantee this will absolutely never happen.
You are correct, but does that make it any less of a good goal? Should we not worry about corruption because there will always be corrupt people? Should we not try to help the poor because there will always be poor? If you simply give in to defeatism, you will always be defeated. To give up on living justly is to give into the worst forms of evil.