That may be true, but the premise I was rebutting with this example was that only children of citizens could be citizens.
Any departure from the plain statement of birthright citizenship in the 14th Amendment just makes things worse. The crack into which people are driving the wedge is, "subject to the jurisdiction thereof," which is being variously interpreted as a cage match between legal immigration status and domicile. If you are here only temporarily, but have legal status, you may or may not be considered "subject to the jurisdiction of" the United States for the purpose of determining your child's citizenship. If you intend to be here permanently, but arrived unlawfully, you may or may not be considered "subject to the jurisdiction of." In the latter case you have clearly established domicile in the U.S., and thus your children should be considered citizens, but you are still somehow magically allegiant to the country you came from. In the former case you filed the proper paperwork and are thus "subject to the jurisdiction of," but you lack domicile. See how making it up as you go doesn't solve the problem?
U.S. v. Wong Kim Ark got it right. Wong was unquestionably a U.S. citizen even though his unlawful immigrant parents returned to China. "Subject to the jurisdiction thereof" means simply to exclude foreign diplomats and (at the time) indigenous peoples. The latter was fixed by statute. The former remains in force: diplomats are not subject to U.S. law—they have diplomatic immunity. Their primary allegiance remains to the country they represent while in the U.S.