During World War 2, allegiance played a very significant role. After all, many countries were involved in the war.
Concerning Japan, they attacked Pearl Harbor out of the blue. It was not expected, in fact they weren't supposed to. Japan was also known for its cruel acts in its invasion of China, and Japan was on the same team as Germany. So in short, Japan was a big enemy.
This did not look good for Japanese American citizens. People were worried of their own safety. National Security was threatened according to the public and the government. So for "safety" measures, Japanese American citizens were forced out of their homes and moved into camps till the war was over. They had limited rights during that point.
Summary: Unfairly because Japan was an enemy of the United States and people were cautious of Japanese American citizens.
Whether it was justified or not is up for debate. The right answer would be no or else you would seem like a bad person. However, you should put yourself in the American's shoes. It was a very huge, and bloody war where safety was not guaranteed for citizens. That's right, countries conscripted citizens and killed citizens during the war, in what you may call Total War. If people whose background came from the enemy's country lived with you, the situation would likely make you distrustful or worried too. Fear limits the person's mind.
