I certainly missed the part where it said "natural born citizen." That is not in the 14th amendment at all.
Not even the Union officers would have bought into the idea of slaves being natural citizens when they were born, from a law that didn't happen until years after their birth.
Laws do not reverse cause and effect. Time flow is maintained as linear. You cannot be retroactively "natural born."
This makes as much sense as saying a man can become a woman.
It's right there, "All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States..." Those not naturalized are natural-born since those are the only two types of citizenship identified by the Constitution.
Not even the Union officers would have bought into the idea of slaves being natural citizens when they were born, from a law that didn't happen until years after their birth.
I wasn't aware that it was their call.