They quote approvingly of him being “native born” and that status allows him to run for President.
Unless they were being very sloppy, if they agreed with your concept, they should have said that he was both native born and natural born, and the latter allowed him to run for President.
It is possible for a court to write sloppy, but that normally isn’t assumed to be the case in a Supreme Court decision.
I agree with you about how it ought to be, but disagree with you on how I think a court will rule based on this decision. I also think no court will rule unless forced to by a carefully thought out case that leaves them no other option.
But, once again, like Elg, they are also considering the citizenship status of his father at the time of his birth when they came to that conclusion, as quoted from the case here:
"The facts were these: one Steinkauler, a Prussian subject by birth, emigrated to the United States in 1848, was naturalized in 1854, and in the following year had a son who was born in St. Louis."
So as the Court noted, he was a "native born citizen" whose father was a citizen of the U.S. before he was born. So then by all means, by virtue of those two factors, he could run for the Presidency. Those two factors together qualify him as a Article II natural born citizen per Vattel.