My guess is that one big reason that Japanese Americans were interned while the German Americans and Italian Americans were not is that FDR was a racist just like his mentor, Woodrow Wilson. FDR could have desegregated the armed forces during World War II. FDR chose not to. Truman did it.
If it was purely racial, why did it only apply to the West Coast instead of nationally?
Of course FDR was a racist. American war propaganda was racist as well.
Dr. Suess explicitly supported putting the Japs in concentration camps in his cartoons:
http://www.tofugu.com/2013/02/20/dr-seuss/ (scroll about 1/3 down).
http://en.wikipedia.org/wiki/Anti-Japanese_sentiment
http://en.wikipedia.org/wiki/File:Anti-Japan2.png
A review of the facts of Japanese behavior in places like Nanjing and Bataan makes the anti-Japanese sentiment understandable. It doesn’t excuse putting American citizens in concentration camps.
