I completely agree with you here. Many of the politicians who propose, as a political philosophy, that charity can take the place of social programs, are hoping to paper over their cruelty. Half of them probably do little to nothing for charity themselves, or (like Trump, say) have elaborate schemes that make it look on the surface like they give to charity when really they are just enriching themselves with financial engineering.
I don’t think that people who give to and do a lot of work for charity do so because they have calculated that the positive feelings they get are worth the time/money. But anti-social machiavellians represent only a very small percentage of the population, while they seem to represent a very significant percentage of English-speaking right wing politicians.