The only Japanese-Americans who could pose a risk were in Hawaii, and they were not interned.
My dad's best little kid friend in WWII was a German kid who's parents were first generation Americans. The kid got beat up a lot, but his parents, who spoke almost exclusively German, were never put in an internment camp. Besides, wouldn't it be really easy for Johnny Jihad (an all-American looking boy) to merely lie about his religion and avoid internment?
There were about 10,000 Italians and Germans interred in Montana during WW II. Japanese were interred during the same period of time on the west coast because they could watch troop and ship movements. We were at war and the military were given the leeway to determine what action was needed, and it was done. I am fairly sure Japanese were interred on the islands of Hawaii. It seems to be a fact that is commonly known, whether it is true or not.