I am saying evolutionary morality as a whole is an invalid concept that is irrelevant to the subject of morality.
Actually, I can think of a minutely useful aspect of evolutionary morality: It tells us the evolutionary mechanism by which we got our current intuitions about morality is stupid because it is also the same mechanism that gave lions the intuition to (quoting the article I linked to) 'slaughter their step children, or to behead their mates and eat them, or to attack neighboring tribes and tear their members to bits (all of which occurs in the natural kingdom)'.
If the mechanism by which we got our intuitions about morality is stupid, then we learn that our intuitions are completely irrelevant to the subject of morality. We also learn that we should not waste our time studying such a stupid mechanism.
So I certainly agree that that facts about evolution don't imply moral facts. But the way you talk seems to imply you think there are other ways to discover moral facts. But I doubt there are objective justifications for human morality that are any better than justifications for lion morality. In terms of what we actually end up valuing biological evolution (a long with cultural transmission) are hugely important. Certainly a brain module for altruism is not a confirmation of altruistic normative facts. But if we want to learn about human morality as it actually exists (say, for the purpose of programming something to act accordingly) it seems very unlikely that we would want to neglect this research area.
Do you believe in an objective morality capable of being scientifically investigated (a la Sam Harris *or others*), or are you a moral nihilist/relativist? There seems to be some division on this point. I would have thought Less Wrong to be well in the former camp.
Edit: There seems to be some confusion - when I say "an objective morality capable of being scientifically investigated (a la Sam Harris *or others*)" - I do NOT mean something like a "one true, universal, metaphysical morality for all mind-designs" like the Socratic/Platonic Form of Good or any such nonsense. I just mean something in reality that's mind-independent - in the sense that it is hard-wired, e.g. by evolution, and thus independent/prior to any later knowledge or cognitive content - and thus can be investigated scientifically. It is a definite "is" from which we can make true "ought" statements relative to that "is". See drethelin's comment and my analysis of Clippy.