Their marriage was Void Ab Initio
Your ipse dixit statement overlooks that a Hawaiian court entered a decree of divorce on March 20, 1964 dissolving the bonds of matrimony between Stanley Ann and Barak H. Obama, Sr. Significantly, the decree of divorce did not annul the marriage.
Until you or someone else gets the Hawaiian court to enter a nunc pro tunc order and rule that the marriage was void ab initio, the law views Stanley Ann as married when she gave birth in 1961 and so 8 USC 1409 does not applicble in the analysis of whether the Telepromptee in Chief is a "citizen" under 8 USC 1401.