Schultz is a german name. Maybe they didn’t want that getting out.
I think it unlikely that was an issue.
Even in the earliest days of WWII the USG did not treat Americans of German ancestry with anything close to the degree of concern with which it viewed the Japanese. Additionally, we had been in open conflict with German naval forces in the Atlantic prior to December 7, 1941 and while there may have been relatively minor local instances of hostility there was a sizable presence in our nation of those with German ancestry that was well regarded.