1)The person in your case was not a natural born citizen.
2)The person in your case was not a minor child adopted into a country that does not allow dual citizenship.
3)Despite the verdict The laws of this nation still say that if you participate as a citizen in another countrys election i.e. voting you will lose your citizenship.
4)The law used to attempt to remove the citizenship of a naturalized citizen that had previous swore a sole alligence to this country.
I hereby declare, on oath, that I absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty of whom or which I have heretofore been a subject or citizen; that I will support and defend the Constitution and laws of the United States of America against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I will bear arms on behalf of the United States when required by the law; that I will perform noncombatant service in the Armed Forces of the United States when required by the law; that I will perform work of national importance under civilian direction when required by the law; and that I take this obligation freely without any mental reservation or purpose of evasion; so help me God.
The question and I do believe it is still a valid one is that if another nation that does not allow dual citizenship confers citizenship on an adopted child during the legal process of adoption is that child or adult in Obamas case still a US citizen natural born or even naturalized if the person in question did not reaffirm their right to their US citizenship at the age of majority as required by US law?
You are using a case that is nothing like the question, save for the fact that both involve the issue of lost citizenship. perhaps you should read more case law until you find one that is more appropriate to the question at hand
So what? The situations don't have to be the same. All that matters is the Court's holding. Read it again:
We hold that the Fourteenth Amendment was designed to, and does, protect every citizen of this Nation against a congressional forcible destruction of his citizenship, whatever his creed, color, or race. Our holding does no more than to give to this citizen that which is his own, a constitutional right to remain a citizen in a free country unless he voluntarily relinquishes that citizenship.That's the Constitutional law regarding loss of citizenship, and it's been the law for decades. Obama never voluntarily relinquished his American citizenship. End of story.
Vance v. Terrazas is a good followup case, and it confirms everything I've already told you.