But what if I think the thief should have his hands cut off, one neighbor thinks he should be fined, another thinks he should be imprisoned, and yet another thinks he should just be let go? So I chop off his hands, my neighbor disagrees with what I did, but what I did was just as right as what he would do since there's no law governing these things, but he disagrees so he stabs me, then my brother gets angry and shoots him for stabbing me, etc etc. Anarchy = chaos.
But you seem to be very trusting of human nature. I'm not.