In "A Reply to Professor Haldane", published in "Of Other Worlds", C.S. Lewis said the same thing as golergka. Lewis said that a robber baron may be satisfied with enough money (though I must say that history doesn't supply much hope of that). The robber baron may get lazy. And maybe, since on some level they know that what they do is morally sketchy, they may repent. But an idealist who holds their ideal or political theory with the force of a religion is far worse, because they commit their horrors in the name of doing good, and so their benevolent impulses seem to them to be temptations - something to be resisted in order to do what is "good".