Let me reword that, as that might be, in one sense, overstating the point a bit.
The case asked the question of whether Wong was a citizen.
The Court examined the question at length, and quite clearly found that he was a natural born citizen.
So in the final declaration, because the question before the Court was, "Is Wong a citizen?" they answered, "Yes, Wong is a citizen."
But the entire core reasoning of the case was that he was a NATURAL BORN CITIZEN.
Since the entire core reasoning of the case determined that he was a NATURAL BORN CITIZEN, and that core reasoning was... well, THE CORE REASONING, completely and absolutely central to the outcome of the case, then that CORE REASONING - and its CONCLUSION, that anyone in Wong's situation is a natural born citizen, is absolutely binding precedent.
I hope that's stated a bit better.
Incorrect. Gray stated the exact question very specifically in the ruling.:
"The evident intention, and the necessary effect, of the submission of this case to the decision of the court upon the facts agreed by the parties were to present for determination the single question stated at the beginning of this opinion, namely, whether a child born in the United States, of parent of Chinese descent, who, at the time of his birth, are subjects of the Emperor of China, but have a permanent domicil and residence in the United States, and are there carrying on business, and are not employed in any diplomatic or official capacity under the Emperor of China, becomes at the time of his birth a citizen of the United States."