An action is moral if there are no better alternatives to it.
Economists espouse the idea of opportunity cost. Life consists of choices. Those choics are between various options, and picking one means not picking all the others. The best option not chosen is the opportunity cost. For moral decisions, there is also an opportunity cost.
Unfortunately, it is all too common to encounter a non-profit organization that does not use its donations wisely. Giving to them anyway is considered morally good by most systems of moral philosophy. However, economists might argue that you are failing to get the most charitable value for your money and thus it is actually wrong to give to those sorts of organizations.
Economists are often accused of playing devil’s advocate. That’s somewhat correct and somewhat incorrect. Economists have the ability to look at difficult situations critically and really ask what the best option is. Non-economists try to opt out of the situation entirely, but that’s not a real option. As the great philosopher Geddy Lee once said “If you chose not to decide, you still have made a choice.” Outlawing difficult choices simply means people in those situations have to pick one option instead of getting to chose themselves.
Examples of subjects where economist morality is better than common sense morality:
Child labor laws
Job creation on wasteful projects/broken windows – Ironically justified by economics