Why do people seem to mean different things by "I want the pie" and "It is right that I should get the pie"? Why are the two propositions argued in different ways? This seems to be because "I want the pie" is too direct, too obvious; it violates a social convention of anti-selfishness which demands a more altruistic morality.

People use both moralistic and altruistic claims hypocritically, but altruism and moralism aren't the same thing. Morality is based on the idea that people deserve one thing or another (whether riches or imprisonment); what they deserve is in some sense part of the objective world: moral judgments are thought to be objective truths.

For the argument that morality is a social error that most of us would be better off were it abolished, a good source is Ian Hinckfuss, "The Moral Society." AND my "morality series."