Because the whole point of the NBC clause is to assure that the president is loyal only to the United States. The framers were smart enough to know that a child gets his or her values from their parents and thus the requirement that they must be American citizens.
Do you really think that the founders intended for a person whos mother made it anywhere to American soil just as the baby was born is qualified to be president? Even though the mother and father could be died in the wool communists loyal to an enemy of the United States? I don’t think so.
This issue must be decided by the supreme court. Let the court cases begin !! No way for the courts to dodge the issue on standing. SCOTUS had better get warmed up.