There were plenty of known Japanese spies and saboteurs in the mix. Lots of Japanese and Americans of Japanese ancestry (some of whom had been sent back to Japan for education/indoctrination) lived on the West Coast, and were more than glad to help Japan’s war efforts. Taking them out individually would have meant compromising the fact that we had broken some key Japanese codes. A great book on the subject with much original material reproduced:
Magic: The Untold Story of U.S. Intelligence and the Evacuation of Japanese Residents from the West Coast During WW II
http://www.amazon.com/Magic-Intelligence-Evacuation-Japanese-Residents/dp/0960273611
I agree completely about those Americans who took advantage of a bad situation.
Thank you!! A voice of sense! I grew up with a lot of Japanese farming families, and virtually all of them understood and accepted the necessity of the camps and bore no grudges.