Both registered for the draft in 1917. Their draft cards had three options for citizen status: Natural-born, naturalized, or alien. They checked “natural born” (of course)
They were anchor babies, naturalized by an act of Congress.
my grandfathers were not naturalized despite having German and Irish parents
They were granted citizenship by a misinterpretation of the 14th Amendment. It was actually meant to only grant citizenship to the children of slaves. (and not even American Indians)
my father (and my mother) were also not natural born, despite being born in New York City in 1923 and 1924, and that therefore I am also not natural born, since my parents were never naturalized.
The government recognized your grandfathers' anchor baby status (naturalized) so all your parents were natural citizens....as are you.
...draft cards issued in 1917 with three categories of citizen status were wrong to describe a person born in the US as “natural born”?
They checked the wrong box.
“citizen at birth, but not natural born”. Do you have any examples of such a person?
Your grandfathers.
Did either of your grandfathers ever run for President?
What act of Congress was that?