I just read them and it sounds as though the meaning is if you go after Italian dual citizenship then you would not qualify as a NBC.
IOW if someone holds passports from two countries, they would not be a NBC.
That position makes no sense, though. First, how would an act I perform as an adult (getting an Italian passport) change my status as "natural born"? Note the word "born" in there. Second, under Italian law, I'm already a citizen, even though I don't have a passport and they are, in fact, completely oblivious to my existence. Simply applying for a passport doesn't grant me citizenship--I already have it in their eyes.