Why was I amused? Because there are no written sources from the era of Abraham that could reasonably be expected to mention him. So the only source of information that could shed light on Abraham's era is archaeology.
And any respectable archaeologist would know that there is no way, from the archaeological record, to declare the nonexistence of a particular historical individual.
As the saying goes, "Absence of evidence is not evidence of absence." For instance, for many years many archaeologists were convinced that the great Maya city-states of Mesoamerica were peaceful — in part because there were no signs of fortification.
Then Mayan writing was finally decoded and translated, and the newly available historical records made it clear that warfare between Mayan city-states was constant and far-reaching.