But even if we take this argument to be an argument not for God’s existence, but just for supernaturalism, it still fails. I agree with [William Lane] Craig that some moral judgments (such as ‘rape is wrong’) are not relative to society or culture. What I don’t understand is why Craig believes this position is coherent only if supernaturalism is true. He says very little about this in the debate. In fact, instead of responding to the most serious thinkers (both theistic and atheistic) who disagree with his position, he wastes his time quoting atheist thinkers who agree with him. Craig may win debating points this way, but he loses logical points. An appeal to authority, even a well qualified authority, is fallacious if there are many equally well-qualified authorities who deny the claim in question. Craig is well aware of the fact that many excellent philosophers (including the greatest Christian natural theologian of the twentieth century, Richard Swinburne) reject his claim that an absolute right and wrong requires God or any other sort of supernatural being. So finding atheists who agree with him on this point is evidentially worthless. In fact, it may even mislead the audience by making it appear as if the only way an atheist can challenge Craig’s argument is by claiming that the wrongfulness of acts like rape is relative to society or culture. To make matters even worse, Craig goes so far as to say that the atheist must deny that rape is ‘really wrong.’ But this wouldn’t be true even if atheists were committed to sociocultural relativism. Craig’s doesn’t seem to realize that some versions of relativism allow for the possibility that a society or culture can have mistaken views about morality, and thus allow for a distinction between something being believed to be wrong and its being really wrong. (italics and boldface added)
Paul Draper, “Craig’s Case for God’s Existence.” In Stan W. Wallace, ed. Does God Exist? The Craig-Flew Debate (Burlington: Ashgate, 2003), 148.