When writing opinion for the NYT [thank you David Sobel for calling my attention it, and for exploring some of the issues raised by it on facebook discussion], a philosophic heavy, NYU's Paul Boghossian, might be expected to rise above the equation of moral relativism with nihilism. (He finds himself in surprisingly good company of your neighborhood Straussian or George Bush.) Like a good Dogmatic, Boghossian's first strategy is to limit the option space: "When we reject absolute moral facts is moral relativism the correct outcome or is it moral eliminativism (nihilism)?" Ahum...what about moral skepticism, agnosticism not to mention quasi-realism, projectivism, constructivism? Of course, writing for a public audience we should keep things simple, but the cause of philosophy is not aided by name-calling ("nihilism") of opposing positions.
The core of Boghossian's argument is that “right” and “wrong” are essentially "normative terms, terms that are used to say how things ought to be, in contrast with how things actually are." (Again, note how the distinction rules out other options.) He offers an example in which it appears that these terms are "absolute" (like commandments). Boghossian then makes life easy for himself by treating the (supposed) relativistic rules of etiquette as the main model that inspires the moral relativist. He concludes, "the relativism of etiquette depends on the existence of absolute moral norms." But this is silly. Etiquette depends on the existence of a relatively stable political and legal order, not morality. (In fact, as political disorder increases, etiquette tends to become more strict, but let's leave that aside.) It is only when one understands etiquette in contrast with an absolute morality that Boghossian's position must seem trivially true. (But that is because at heart Boghossian cannot take etiquette seriously.) In fact the relativity of legal/political language/orders provide far better models for moral relativism than Boghossian considers.
For example, legal language is suffused with normative language (in Boghossian's sense); even a Legal Positivist would accept that. (The Legal Positivist would deny, in fact, that morality explains this, and would appeal to social facts--so at least one position accounts for the very normativity of legal language by denying that absolute moral norms are presupposed by it.) Yet, nearly all of legal language is relative to some jurisdiction. Only a child fails to understand that the law of the land expresses itself in absolute terms (to use Boghossian style example: "no speeding above 65miles/hour"), while having no reach abroad. (This is not incompatible with some laws having a wider scope.) If (the language of) law can be normative, relativistic, and does not have to presuppose morality, then it is a workable model for the moral relativist to appeal to. This is a coherent non nihilist position (it would have surprised Aristotle that his position devolves into nihilism.) And that's all I am arguing here. Is it true? Well...that depends on your perspective...;)