I think that while some parts of natural human morality may rest on illusion, hedonically grounded practical reasons, and at least those parts of morality that rest on them, very likely have some objective normative standing.

Leonard David Katz, Hedonic reasons as ultimately justifying and the relevance of neuroscience, in Walter Sinnott-Armstrong (ed.) Moral Psychology, Volume 2: The Cognitive Science of Morality: Intuition and Diversity, Cambridge, MA, 2008, pp. 409–417, p. 409