Does anyone actually believe in Objective Morality? Aren’t the Religious just the Ultimate moral relativists?
Before going on the phrase "objective morality" must be addressed. What does it mean to be objective? If something is objective then it is a property of the object being studied. If something is subjective then it is derived from the mind of the subject observing the object.
I will use an example to illustrate the distinction. If I say that light being refracted through moisture in the air creates a spectrum of visible light that we call a rainbow, then I am making an objective observation of a property of the object being studied. If I say that rainbows are beautiful then I am making a subjective statement as the distinction "beautiful" is not a property manifest of the object, but rather a definition that emerges from the mind of the subject observing the rainbow. In other words, whether we existed or not a rainbow would still be refracted light caught in the atmosphere, but without a mind to observe it the rainbow could not possibly be "beautiful".
In this way there cannot be objective morality. "Right" and "Wrong" are not properties of objects or events; they are manifest only in minds capable of observing those objects or events, and therefore must be subjective.
Now what about the scope of Morality? When a Theist says Objective morality, they tend to mean that said morality is universal, that a given act is right or wrong here, in China, on the Moon, or on Orion’s belt. Locality is not particularly relevant. We use "Objective Morality" as a shorthand, but what most Theists really mean would be better represented by saying "Universal Objective Morality".
Even if I grant for a moment that there is a God, no Theist would ever dare suggest that there is truly universal objective morality in the Cosmos. Truly objective morality would be an in inherent property of the Universe. For it to be objective this morality must, by definition, be a property of the universe, not a judgment subject to a mind, even the ultimate mind, observing the system. The most ardent apologist must admit that the morality they believe in is still subject to at least God himself if nothing else. A Theist believes in subjective morality, simply disagreeing with the Atheist about whom that judgment should be subject too.
I can only assume that the use of "objective" to describe the morality of God started as a somewhat metaphorical or abstract theologians phrasing, which was adopted by the common public, who never stopped to consider what they actually mean by "objective" and just kept reciting the phrase as a mantra.
In any event, unless you are prepared to present God as an Object, Morality as a property that can exist independent of a mind to determine it, or offer a new definition of Objective, the idea that there is such a thing as objective morality, or that God is the source of it, is rendered as nonsense.