Moral relativism has been co-opted by the absolutists as a sort of strawman, much like the concept of "macroevolution". There is no such thing as macroevolution, you see, only microevolution applied over millions of years, but its fun to put scientists on the spot by tossing the word macroevolution at them and making them defend it when they don't even hold that position.
Same goes for "moral relativism" which absolutists critique using nothing but word salad while social Darwinism quietly takes over the mainstream discourse in the same way evolution inexorably displaced creationism. A more accurate name for equilibrium morality is moral naturalism: evolutionary game-theory applied to ethics.
Rather than interpreting morality as the result of negotiations between members of a large group of free moral agents, moral naturalism sees morality as an emergent phenomenon arising as an unintended side-effect of the interaction of those agents in smaller groups.
In other words, morality is not to solve a single problem but a number of recurring problems, in the same manner that natural selection adjusts populations of organisms for changing environmental conditions.
This puts moral facts in a class with natural facts about the world, which contradicts the assertion of divine command theory that morality is defined by the arbitrary revelation of God.