Americans in WWII were not very worldly.
in 1941, most Americans had never eaten Pizza or Chinese food and the wide world beyond the county line was a great mystery.
In short, they were simple rural hicks:
Me and Dan "hanging out" at the ranch
Todays farmers are much more worldly:
However, Rural Americans in WWII were terrible at distinguishing between Asian people, saying "they all look alike to me".
Even the beloved "Dr. Suess" parodied Japanese facial features:
Check out this article from LIFE Magazine in titled "How to tell Japs from the Chinese".
Today this would be terrible racist, but many rural Americans had never seen an Asian person, and it was a matter of life-and-death that they be able to distinguish the good guys from the bad guys:
How to identify a Japanese enemy