Based on what evidence, other than that you think so?
If I were looking for "relict" populations I'd look for refugia, like perhaps in the Appennines, not near Napoli. You are aware that it's not only a port but that the surrounding countryside is a fertile, FLAT plain traipsed over by everybody and his brother, yes?
As to Etruscan descent people carrying more Iberomaurisian, I think Pax addressed that quite nicely. The latest papers do not see that one admixed sample as denoting any significant presence or continuation of "North African" ancestry in Etruscans.
Whether Saracens settled near Salento might have had a small impact I don't know, but Frederick Barbarossa, after using them, crushed the Saracens settled on the mainland, and the Spaniards, once they took over and imported the Inquisition, soon took care of the rest. Some y dna or mtDna may survive, but I doubt a lot of actual North African remains. I can speak for my husband, with both Neapolitan and Calabrian ancestry, and for the people with whom he shares at 23andme, and while they show surplus "Caucasus" ancestry, the North African is less than 2% in all of them, with most of them having about 1 to 1.5%, hardly anything to write home to mom about.
Perhaps you've forgotten but we've had this discussion before. I'm not aware of any paper changing those essential facts.