What about the case of two citizen parents, who give birth abroad. By all accounts, the child is a US citizen at the moment of his or her birth ("natural-born citizen"), but that child may have additional natural citizenships.
What if one parent is a US citizen who has additional citizenships that may be prohibitively expensive or impossible to abandon?
This question is not all black and white.
Citizen at birth and natural born citizen are not the same.
Natural born citizen was chosen as it excludes those with multiple citizenships.
http://www.art2superpac.com/issues.html