There has been some interesting discussion of the previous post on the Stupid Way of Arguing Against Divine Command Theory. I thought I would put up, as a tangential matter, a few points that (insofar as they are ignored) probably make it easier for people not to notice that there is something very off about the SWAADCT.
(1) Divine command theories are specifically theories of obligation. To put it in other words, they are not concerned with goodness in general but with that particular kind of goodness that can be represented by a strong modality (Box) -- a kind of necessity. And they are positivistic about this: you only have an obligation (strong modality/Box for morality) if something commands or forbids something.
They are not general accounts of goodness I have never come across any developed version of divine command theory that was even consistent with taking divine command theory to be a general account of goodness. The most important divine command theorist in the early modern period, William Warburton, rejects this entirely, unless by 'goodness' you mean 'having to do strictly with moral obligation'. Warburton's account recognizes that we have three distinct ways in which we talk about morality. We talk about morality in a rationalist way (perception of what is appropriate), we talk about morality in a sentimentalist way (good taste), and we talk about morality in a deontic way (following or not following obligations). The weakness of the former two is that they both admit of degrees. Yes, murder is generally a stupid way of getting what one wants, and yes, it is icky and bad taste. But lots of things are stupid and icky that are not necessarily violations of moral obligations; so what makes the difference? Command and sanction, which draw a sharp, bright line. When Warburton argues that atheists cannot consistently be moral, he is not arguing that they can't identify things as good and bad; he is arguing that there is no way to pull deontic necessities, obligations, out of the slippery, fuzzy means they can consistently accept, and that the only way to have such obligations is to have some universal command and sanction, which requires some commanding authority with universal power of sanction.
If we look at other kinds of divine command theory, like, for instance, the more modern version explored by Robert Adams, we find the same thing: there are kinds of goodness and badness independent of obligation and permission, it's just that for the latter kind of goodness you need something that can obligate and permit. And so it is with others.
(2) The God of divine command theory is not generally an empty placeholder; he has to have the features required to have commanding authority of universal scope. In Warburton's account these are absolute goodness, wisdom, and power; in Adams's account, love is specifically, although not exclusively, singled out. Such divine command theories -- and, again, all developed divine command theories I've ever come across give some content to what it means for God to command -- do not accept the view that just any kind of thing can be commanded by God. In Warburton's case, we cannot ever say that God might command something unless we have reason to think it is the kind of thing that a perfectly good, wise, and powerful authority might command. In Adams's account, nothing counts as the right sort of command to form an obligation unless it is the kind of command a loving God could give. Thus none of the usual scary scenarios can be easily shoehorned in. To posit that there might be a situation/possible world/whatever in which God commanded that we should cannibalize schoolchildren, we'd have to first determine that we had good reason to think that there was a situation/possible world/whatever in which a perfectly good, wise, and powerful (or loving) authority might have wise and good (or loving) reason to require that people cannibalize schoolchildren. Once we've gone out this far on the limb, it's easy to see that the supposed scary scenario is completely toothless, even before we've gotten to the question of obligation itself.
(3) By the time we've even gotten to the question of divine command and obligation, though, we have already assumed, for the sake of argument, that there is no impediment to its being the kind of thing we could be obligated to do. All that's missing is whether we actually are. And since divine command theory is positivistic about moral obligation, the bare fact of God, as having these authoritative qualities, commanding whatever it is constitutes the obligation. Once we've said, then, "Assume that DCT is true, and assume that X might be commanded by God; then it's obligatory!" we aren't saying anything that could possibly be an objection to divine command theory: we have simply said that if we assume that divine command theory is true and that such-and-such might meet its criteria, we would have an obligation. This is a purely formal characteristic that divine command theory shares with every possible account of obligation. That's just what it is to be an account of obligation: that if something, whatever it may be, meets the criteria, it is an obligation. It does not follow from this that X actually might be commanded by God -- again, I have never come across a divine command theorist who was definitely committed to saying that absolutely anything might be commanded by God. All we've done is restate what it is to be an account of obligation, using divine command theory and some arbitrary example. To make the example non-arbitrary we have to show that the divine command theorist is committed to its being a possibility.
(4) Given the structure of most divine command theories, it's actually quite implausible to accuse them of implying that anything could be an obligation. What they are usually committed to instead is the claim that anything might not be an obligation. Take any obligation in existence, God could have conceivably not made it an obligation. Note that it could still be a good thing to do. Likewise, for anything we are obligated not to do, the divine command theorist is not saying that God could have made it so that we were obligated to do it (which would have to be proven on a case-by-case basis) but rather that God could have made it so that we were not obligated not to do it. It could still be bad, stupid, icky, distasteful, inappropriate, etc., depending on the exact form the divine command theory took. We just wouldn't have an actual obligation not to do it; doing it might make you an icky, stupid, bad person in some way, just not in the way that failing in your duty might.
When we recognize this, we see quite clearly that most critics of divine command theorists are probably guilty of a scope error, confusing God could have made it so that we were obligated to do it with God could have made it so that we were not obligated not to do it. But you can reject the first while accepting the latter, and most divine command theorists at least tend to prefer to talk about the latter, and at least seem committed to rejecting the former, whenever we are talking about Very Bad Things. Divine command theory is not the position that God could make anything obligatory; it is the position that anything obligatory can only be so because God commands it. These are radically different.