The Supreme Court recognized two classes of citizens who are not naturalized but who may be citizens by birth. One class were those children born in the country to parents who were its citizens. The other class, the court said, is recognized by “some authorities” as citizens by being born in the country without reference to the citizenship of the parents. The first class were citizens with no doubts, while the second class have doubts about their citizenship that would need to be resolved. Only ONE of these two classes was characterized as natural-born citizens: those born to citizen parents. They said this in rejecting an argument based on a woman claiming her citizenship via the 14th amendment. By rejecting that argument, the court exclusively charactered those born to citizen parents as natural-born citizens. There would have been no doubts she satisfied the lesser requirements of the 14th amendment because she was obviously born in the U.S., but the court categorically said her citizenship (and by context, ALL persons born in the country to citizen parents) was NOT conferred through the 14th amendment. That exclusion makes the NBC definition exclusive and materially distinct from 14th amendment citizenship by birth. They used this definition to specifically satisfy the meaning of the term natural-born citizen in Article II in the Constitution, which is why 40 years later, the SCOTUS cited this decision specifically as precedent on presidential eligibility.
That is obviously your opinion of what it meant. The prevailing legal opinion is that of US citizens, only naturalized citizens are not natural born. The Constitution clearly only envisions three types of US citizen.