‘It would be practicable only in a world of people who are …’ <—(no moral words allowed)
close to god? have the same name as someone from the bible? be people that you lionize? have wings? have not committed any act contrary to the 10 commandments?
Not it’s not. It is absolutely terrible, and far worse than the NAP. First of all, in many cases you would not know if you are reducing the amount of social cooperation is society. Also, practically every criticism of utilitarianism could be refined and applied to this theory. Then there is the fact that different people have different ideas as to what constitutes an increase in “social cooperation” in society.
It is also not true that all thieves reduce the amount of social cooperation in society. Maybe I steal a painting, and the entire community cooperates together in order to return the painting to its rightful owner. In this example, the thief has increased the amount of social cooperation in society.