is that the ideas that support this behavior - objectivism, supply-side economics and the like - are quite literally, for many conservatives, matters of faith in the religious sense. And by "religion" I mean any belief system that involves accepting certain things as true without any objective proof that they actually are true. Paul Ryan, for example, apparently believes that taking away government-supplied health insurance and replacing it with private insurance and vouchers is a good thing - notwithstanding the fact that an objective analysis of the costs and benefits shows that this would actually harm people.
Of course supply-side economics has been proved over and over not to work, but conservatives are convinced it does, or that it will if it's tried often enough and for long enough. Likewise, Marxists, Maoists and Stalinists believed communism would work, and for decades kept trying to make it work even though it clearly wasn't working at all. And Ryan believes absolutely in his health insurance program in much the same way Christians believe Jesus was resurrected on Easter. Unless we accept the possibility that all Republicans are truly evil so they promote legislation that hurts people because they like hurting people (which may be true in some cases), the only explanation is that they believe their own bullshit and think that eventually the implementation of their theories will actually improve society.