It is a way to direct and semi-control the actions of ignorant, self centered people without building a real world justice system.

It works only to the extent you can convince impressionable young minds to accept it.

For the less impressionable, there is enlightened self interest --- understanding and accepting that the world would be a better place for all if everyone would simply do unto others as you would have them do unto you.

Unfortunately, the latter has yet to reach a similar level of acceptance and popularity --- but there is always hope.