You are making the assumption that there are moral truths. Where do these come from? Moral error theorist (i.e. those who hold that all moral judgements or a significant subset thereof are systematically false) like myself would say that our mora beliefs stem from affective attitudes that we project on the world and misinterpret as moral facts. A plausible explanation for why this is the case is that this projection and objectification of our values favored the survival of the genes of our ancestors. But because we can explain why we take our moral values to be objective and authoritative without presuming the existence of moral facts, then parsimony dictates that moral facts are entirely superfluous to our understanding of morality. And so moral nihilism looms.

That is not to say that a moral nihilist cannot make moral judgements. We can take a fictive stand towards morality where we just pretend to believe in morality (Richard Joyce's moral fictionalism). Another option is to compartmentalize our beliefs about morality, where the advice is to believe in morality on a day to day basis, but to believe that morality is false in more critical, detached contexts (Jonas Olson's moral conservationism). This latter position is also my own; mostly because it seems psychologically impossible to both avoid moral judgements and at least sometimes believing that they are true. There are a few other positions, but I won't venture to explain those.

As for your fear that morality would be used dangerously, it was not my intention to give the impression that I do not want people to be aware of the subjective roots of their morality. (Which you might still deny, I understand that.) What I meant by saying that we can use psychological mechanisms like in the article for our advantage, was to say that I want everyone, not just a small elite, to be able to stand back from moralizing in critical contexts (such as when thinking about the nature of morality and their values) and to shape their morality in this context. It is only by having a large portion of the population engaged in shaping our moral norms that we can reach some kind of reflective equilibrium where our moral intuitions (such as the one that we won't hurt our neighbors) are best synchronized with each other.

But the only reason why we would continue to moralize in the above scenario is because of its usefulness and that it has beneficial effects on people's actions. Not because there is an actual truth of the matter.