Why Did the Nazi’s Force Jewish Men to Be Renamed Isreal and Jewish Women to Be Renamed Sara if Their Given Names Were Not on the List of Approved Jewish Names?

I believe the premise of the question is incorrect. Both 'israel' and 'Sara' were included in the lists presents in an Annex to the corollary from 18th August 1938 (I d 42 X/38-5501b), published in the Journal of the Reich and Prussian Ministry of the Interior, vol. 35, 24th August 1938 I quoted in this thread about Jewish names in Nazi Germany.