"research indicates that the moral rules all seem to be elaborations on the same five universal, underlying moral instincts, which would indicate that morality does *not* fundamentally vary"
Did you read this link? I don't know where you got the notion that Pinkner thinks morality doesn't vary.
"The five moral spheres are universal, a legacy of evolution. But how they are ranked in importance, and which is brought in to moralize which area of social life — sex, government, commerce, religion, diet and so on — depends on the culture. Many of the flabbergasting practices in faraway places become more intelligible when you recognize that the same moralizing impulse that Western elites channel toward violations of harm and fairness (our moral obsessions) is channeled elsewhere to violations in the other spheres. Think of the Japanese fear of nonconformity (community), the holy ablutions and dietary restrictions of Hindus and Orthodox Jews (purity), the outrage at insulting the Prophet among Muslims (authority). In the West, we believe that in business and government, fairness should trump community and try to root out nepotism and cronyism. In other parts of the world this is incomprehensible — what heartless creep would favor a perfect stranger over his own brother? The ranking and placement of moral spheres also divides the cultures of liberals and conservatives in the United States. Many bones of contention, like homosexuality, atheism and one-parent families from the right, or racial imbalances, sweatshops and executive pay from the left, reflect different weightings of the spheres."
Furthermore, there is no "evidence" here. This article is theoretical.
Ironically, your friend here also says color is a figment!
Also, elsewhere he says:
"The scientific outlook has taught us that some parts of our subjective experience are products of our biological makeup and have no objective counterpart in the world. The qualitative difference between red and green, the tastiness of fruit and foulness of carrion, the scariness of heights and prettiness of flowers are design features of our common nervous system, and if our species had evolved in a different ecosystem or if we were missing a few genes, our reactions could go the other way. Now, if the distinction between right and wrong is also a product of brain wiring, why should we believe it is any more real than the distinction between red and green? And if it is just a collective hallucination, how could we argue that evils like genocide and slavery are wrong for everyone, rather than just distasteful to us?"
He concludes by saying that moral realism is not feasible, at least in the strong sense.