Great summary. I think a question you could ask (it's also a question moral philosophers ask) is this: Haidt's moral psychology purports social intuitionism. He believes that morality is - at least - an intuitive and emotive idea. How then could we develop a normative theory from this?

If it was true that what people conceive as right and wrong is socially and culturally appropriated, how can we construct a comprehensive (or universal) code of ethics? Would that necessarily mean there's really no right or wrong?