Since archaeologists of the Bible believe Abraham, Moses and David never existed, why defend Israeli nationalism based on these religious stories?
Most who hold this view haven't taken the time to examine the bible and archeological support for the existence of these men. It is to say, that if I don't know you, is it true that you do not exist? Your existence can be substantiated through your lineage which includes witnesses to your life, any artifacts you were associated with etc.
I don't need you, to prove you exist. Such is the case with profound evidence for these men, which includes Solomon the son of David which these same folks I suspect, dispute his existence. What I think you may find is that bible scholars and archaeologist argue time period and location more than existence.