The reference was a side discussion (dictum) because NBC was not an issue before the court; the court was not asked to rule on NBC, nor was its confirmation of NBC an essential part of, or pertinent to, its findings.
Rather the USSC was asked whether the Constitution or the 14thA bestowed on female citizen Virginia Minor the right to vote; the court found against her by reference to those two instruments. I.e., the court did not "hold" or "rule" on the elements of NBC.
Although the decision has enormous persuasive value regarding NBC, the fact later courts referred to Minor’s confirmation of the obvious does not convert Minor to a “ruling”.
I don't mind that you want to disagree, but you haven't given an accurate basis for disagreeing. The NBC definition was NOT a side issue. The court framed the petitioner's arugment as basing her voting rights on being a 14th amendment citizen. That argument was rejected on the basis of natural-born citizenship.
The argument is, that as a woman, born or naturalized in the United States and subject to the jurisdiction thereof, is a citizen of the United States and of the State in which she resides, she has the right of suffrage as one of the privileges and immunities of her citizenship, which the State cannot by its laws or constitution abridge.
In the underlined part above, V. Minor's citizenship is claimed on the basis of the citizenship clause of the 14th amendment. The court spent the next several paragraphs saying that women didn't need this amendment to be citizens, that they were already citizens and that all citizens before and after the 14th amendment did NOT have an inherent right to suffrage per the privileges and immunities of their citizenship. The court defined NBC to justify their rejection of the argument that was presented.
The Court in WKA recognized that V. Minor's citizenship was part of the finding ... and that her citizenship was due to being born in the country to citizen parents. That's NOT a side issue.
Minor v. Happersett (1874), 21 Wall. 162, 166-168. The decision in that case was that a woman born of citizen parents within the United States was a citizen of the United States, although not entitled to vote, the right to the elective franchise not being essential to citizenship.
WKA says she was a citizen of the states by being born of citizen parents within the United States. This DOES hold on the elements of NBC as you say.