While welcoming your pursuit of rigour here, Sheldon, it's apposite at this moment to factor in a missing part of the puzzle.

One of the aspects of the tiresome apologetics about "morality" we see here from the usual suspects among the mythology fanboys, is the implicit assertion that their choice of imaginary magic man purportedly integrated ethical precepts into the foundational fabric of the universe itself. This is an assertion that among others, Nietzsche was scathing of, when he castigated those philosophers who erected a metaphysics, not for the purpose of illuminating our understanding of, say, cosmology or cosmogony, but for the purpose of imposing an ethics upon the universe, regardless of whether or not the universe agreed with this process. Nietzsche didn't just have mythology fanboys in mind when launching his critique, of course, but had in mind every assertionist hijacker of philosophy, regardless of the stance thereof with respect to 'supernatural' entities. Assertionists of different stripes have a habit of seeking to use an asserted "is" to enforce an "ought", despite the fallacious nature of that process, and Nietzsche's exposure of this canard in operation within the requisite hijacked branches of philosophy, is a service we should be thanking him profusely for.

In the sense that ethical precepts aren't built in to the foundational fabric of the universe, one can of course say that 'there does not exist a morality in nature', but one has to be careful with the precise meaning one intends to impart. I regard the idea of ethical precepts being integrated into the fabric of space-time itself as absurd, because ethical precepts only make sense when there exist entities capable of recognising said precepts and acting upon them. What would be the point of performing such an act of integration, right at the start of "creation", when entities capable of responding thereto would not appear for 13.4 billion years? During the early history of the universe, conditions would not even permit neutral atoms to form, let alone compound entities at the level of, say, a single celled organism, and thus far, the evidence informs us that we had to wait 10 billion years for the latter to put in an appearance (I've already addressed elsewhere the much more interesting question of the large scale ubiquity of life, and this is properly a subject for its own thread). Embedding an ethic into the universe for over 13 billion years before that ethic becomes useful, strikes me as a farcical indulgence to put it mildly.

Of course, none of this detracts from what we actually know about ethical precepts. We know that humans are capable of devising ethical precepts, and, for that matter, systems thereof at a relatively high level of abstraction. We also know, courtesy of that abundant literature I've mentioned elsewhere, that the ability and motivation to formulate and act upon ethical judgements is not unique to our species, though whether other species do so at a matching level of abstraction to ourselves, requires further research to answer of course. We know that the capacity to formulate, and motivation to act upon, ethical precepts is, thus far, a feature of species with well-developed systems of social interaction. But of course, while the capacity for ethical thought, and the motivation to act thereupon, are both capacities with an increasingly well-documented evolutionary and biological basis, the products of that thought are somewhat more troublesome to pin down. While certain basic precepts of reciprocity appear to emerge reliably and repeatably in different lineages, more detailed precepts quickly shift out of the reach of a consensus analysis.

In short, while the existence of ethical thought and ethical behaviour is not in question, and supported by an appropriate body of observational data, the purported "privileged" status of a particular set of precepts, on the other hand, is not merely seriously in question, but considered instead to be an indicator of one of the hard problems in philosophy. Namely, how can we be sure that a given set of precepts deserves our adherence? That question has been exercising minds far greater than those of sleazy pedlars of apologetics on the Internet, and for far longer than any of said sleazy pedlars have even been alive.

And again, in short, the existence of ethical thought and behaviour, does not for one moment mean that one small subset of the products thereof enjoy a "special" status. Though teaching this elementary concept to the usual suspects, is likely to be even less successful than trying to teach spinor calculus to my tropical fish.