The apologetics angle is attractive to both sides of the debate, and for different reasons. It's understandable we'd all go into it: it's hugely interesting and important. But maybe it's a side issue.
Originally, the strand here was about "How to Tell Right from Wrong," and I think we should honour that rather than spiralling off into related issues, if we can. (We could always do an additional strand, if anyone is still sincerely interested in the apologetics discussion.) However, we could easily just grant one another our suppositions...that is, grant that IC is a Christian and that, say, Obvious Leo is an Atheist, or at least a skeptic. That would allow us to do the work this strand asked us to do, rather than the related matter of apologetics.
I'm going to suggest that, for this strand, we try to get back to the original matter and work from there.
The strand began with AS's claim she had an infallible way for Christians to tell right from wrong. She called out Christians, specifically, to respond to it. After a bit, I chimed in with my doubts about the value of that test -- even for the kind of Christians with which she is familiar, but certainly for the kinds with which she is not. I don't see that Atheists here felt they wanted to say much on that particular test...understandably, of course, since the idea of giving account to God is something they deny anyway. So they're being consistent there, so I can hardly fault them for that.
Nevertheless, I think Atheists do have a legitimate interest in the larger question framed by AS, the matter of "right" and "wrong." And the Atheist set has not been reticent to chime in, so I think they all agree that they do have a stake in the discussion. But if the test AS wants for Christians is no good, even for them, then it's certainly of no use to Atheists.
When I left I had put up an opportunity for all the Atheists out there. I had simply put to them HOW they know right from wrong. That is, what is their ground or legitimation for saying X is bad or good. For if, as AS assumes, Christians need some way of testing the matter of "right" and "wrong," then surely so do the Atheists (unless being "Atheist" means being amoral, as Nietzsche thought).
And all I've heard since I put up that opportunity is the crickets chirping.
So I want to put it out there one more time: Atheists, time to step up to the plate (or wicket). Take your best swing.