
I suspect Finn is right about it being a token of patriotism for American immigrants. Those were interesting times, and I doubt many people alive now can understand the encompassing scope of the Second World War, with the draft, rationing, the war effort, recycling, etc.
My great-grandfather was German, and while there were some suspicions, I know he was a secret service agent who did a lot of work for the U.S. government. I am not clear what the family means by "secret service," as to me that means someone who protects the president, but apparently he may have been over seas in Europe. Apparently he never really talked about it after the war.
I wasn't just racism, given that anyone with half a brain knew we would be going to war. There was also the Niihau Incident that caused a lot of alarm.
In Idaho we had a large number of internment camps, and as a result we have a sizable population of people of Japanese ancestry. (I work with a Japanese man whose grandfather and father were in on of the camps).
When I first heard about the Japanese Internment, I asked my dad about it with all the moral outrage of a adolescent. He said one time when he was talking with a Japanese that had been interned, he asked the man about it. The man said, "Thank God we were in America! Any other country in the world they would have just rounded us up and shot us all."
So not that it justifies what happened, but given what was going on in the rest of the world, I'm glad we didn't do that.