I think the incentive is basic empathy. Just because our fellow humans are economically worthless, does not mean they are lesser people. If the point is that t

I think the incentive is basic empathy. Just because our fellow humans are economically worthless, does not mean they are lesser people. If the point is that those people produce no value, they shouldn't work at all. They could just dig and fill ditches, but that doesn't produce value. Amazon also leeches from the public goods, but that is somehow socially acceptable.