> Why does education/intelligence/morality not cull the inner devil of some?
This is honestly a far more complicated question than other commentors appear to be capable of engaging with.
Educational systems worldwide are constructed with the idiotic hope of job fulfillment. There are noises about a liberal arts education, but these are the first things cut when budgets are on the line. Educational systems, thusly, do nothing to help guide moral compasses: indeed, they do a lot to break them down.
Intelligence, on the other hand, very naturally cuts both ways. The capacity to reason is also the capacity to rationalize. These are people trained to vote with their wallet, because their wallet is the only meaningful measure of value they have. Short of coincidence, they have no particular reason to believe that this is untrue.
Morality, though, isn't innate. The purpose of philosophy--one of those casualties of an industrial-catered educational system--is to actually tackle the construction of a moral system and tinker with practical applications of it. It was never a widespread practice to engage in understanding how morals are made, even if you contribute no new thought, but we've done nothing to spread it wider.
We end up leaving it to genetic lottery and your local tradition of faith. When most people's "inner devil" is culled only by the least possible amount of thought, how do you expect it to be culled at all?