Euthyphro's Is My Favorite Dilemma

Last year a Christian apologist named Steve Cornell called me out and sent me a chapter pending publication (and still not apparently online) by Notre Dame professor Christian Smith, entitled "Does Naturalism Warrant a Moral Belief in Universal Benevolence and Human Rights?" I wasn't impressed, and replied:
His paper would be more interesting if he had written it three hundred years ago, before David Hume famously noted the Is-Ought Problem. Smith does a workable job of re-demonstrating Hume's conclusion, and then does a very poor job of trying to show that an insurmountable problem results for the ethical worldviews of naturalists. Smith is a sociologist with no publications in philosophy journals on his CV. If this paper ("Does Naturalism Warrant a Moral Belief in Universal Benevolence and Human Rights?") were peer-reviewed by a philosopher, she would likely complain that Smith fails to mention 1) Hume and the Is-Ought Problem (aka the Naturalistic Fallacy), and 2) the Euthyphro Dilemma (cf. Divine Command Theory), which is the corresponding problem for theists.
Smith assumes without noticeable argument that naturalists must defend the idea that "universal benevolence and human rights" are completely objective "moral facts". He commits an obvious fallacy of the excluded middle when he says the only alternative is "arbitrary, subjective, personal preference". There are choices on the table other than just that 1) morality is completely objective and 2) morality is completely subjective. As I mention in my book, there can be meta-ethical ways to objectively compare alternative subjective derivations of values from objective facts. This is related to what in contemporary meta-ethics is called value pluralism. Aside from one passing mention of "moral realism", Smith doesn't seem to engage the modern literature of meta-ethics at all. For an idea of what such engagement looks like, see Is God Good By Definition? by Graham Oppy.