Really, all the Scotus said was that residency requirements are valid in claiming US citizenship for one who’d never lived here before. (Wasn’t there an age by which it must be claimed?) Until that time, I suppose it could have been viewed as sitting in an inactive file. Failure to act on it, could be seen as the individual acting to drop his citizenship.
It seems to me the principle is that despising your citizenship is the equivalent of renouncing it.
And tell me what child born in the US to American parents would have lost his citizenship for failing to act if he had lived in a foreign country for the rest of his life?
Tell me how an undisputed "natural born citizen" would lose his citizenship for failing to act?