That's pretty much what we do. The difficulty lies in determining what counts as a moral wrong. Some societies have left this in the hands of the judge (or feu

That's pretty much what we do. The difficulty lies in determining what counts as a moral wrong. Some societies have left this in the hands of the judge (or feudal lord). Most modern societies require legislatures to write down the wrongs and have judges enforce them as written. In this fellow's case, society decided that it was NOT a moral wrong. Many people (including the judge) may feel that what this person did (spending money that wasn't his but was available to him because of bank errors) was immoral. But others may feel that it is not ("Hey, he never lied to the bank - that makes it their problem."). As a society, we have decided that we won't let the judges declare something "wrong" unless the legislature had previously criminalized it, and in this case no existing laws applied.