Maybe we shouldn't. Discussion on these forums has never been about whether we should or shouldn't use certain eligibility standards.
We most certainly should not. We should use the highest reasonable standard, and that of being born here to American Citizen Parents is not so unreasonable that 95% of Americans cannot meet it already. Why must we tolerate the introduction of questionable Allegiance into our government?
Given all the evidence which demonstrate the stronger standard is historically correct, why should anyone wish to argue for the legitimacy of the weaker?