So? The same could really be said of any number of people supposed to have lived long ago (Socrates, Plato), who these Davidic disclaimers believe whole-heartedly, without-a-doubt were real.
I wonder why some people have no problem believing people outside the Bible were real with no more evidence to prove their existence than people from the Bible. Could it possibly be the work of someone very subtle, who wishes to keep mankind separated from his Creator?
Karl Marx?