think its because the 14th Amendments ratification
How do you determine which presidents were actually eligible before enactment of the 14th Amendment? What made Lincoln, for instance, a “natural born citizen”, since you seem to believe that people born on US soil to US citizen parents weren’t natural born citizens prior to 1868.
Arthur was rumored to have been born in Canada. This was never successfully demonstrated by his Democratic opponents, although Arthur Hinman, the attorney in charge of the investigation, raised the objection during his vice-presidential campaign and after the end of his Presidency.
Arthur was born in Vermont to a U.S. citizen mother and a father from Ireland, who was eventually naturalized as a U.S. citizen. Despite the fact that his parents took up residence in the United States somewhere between 1822 and 1824, Chester Arthur additionally began to claim between 1870 and 1880 that he had been born in 1830, rather than in 1829, which only caused minor confusion and the incorrect birth date was even used in several publications. Arthur was sworn in as president when President Garfield died after being shot. Since his Irish father William was naturalized 14 years after Chester Arthur’s birth, his citizenship status at birth is unclear, because he was born before the 1868 ratification of the 14th Amendment, which provided that any person born in the United States and subject to the jurisdiction thereof was considered a born U.S. citizen, and because he also held British citizenship at birth by patrilineal “jus sanguinis.” Arthur’s father never relinquished British citizenship. Arthur’s natural born citizenship status is therefore equally unclear.”—From Wikipedia
Chester Arthur is a red herring for the particular matter at hand. I specifically asked what made Lincoln a natural born citizen. It is your contention that presidents prior to 1868 weren’t constitutionally eligible to be president unless congress deemed them as such in their naturalization acts.