“Yup, the Confederacy was a foreign enemy that attacked the United States of America.”
Not according to the offical record: The confederate States never left the union, therefore, they are not, and never were, foreign.
Besides, the Marines allows Mexican flags and swatiska, both were foreign enemies of the USA.
The military allows swastika tattoos? I have a hard time believing that.
Now maybe some skinhead's date said "he's a Marine" but she was wrong.