Judge Not

In Exodus 35, is says that anybody who works on the Sabbath should be put to death.  And I thought, who gets to make that call?  So typical of us humans, we love (LOVE) to judge each other.  I'm sure that throughout history there have been self appointed judges for this law.  Sure, the LORD commanded it as so it must be; but, Moses and Aaron and the judges were in authority under Him.  And, I wonder, how many times was the sentence of death carried out by zealots without authority as we love to condemn our neighbours.