Japanese Americans treated during World War II? Why did some Americans feel this was necessary? Were their fears justified?

Japanese Americans were put into concentration camps in America where they had to live together because they were of japanese decent. many Americans believed this was unfair due to the fact that they were already in America before the bombings of pearl harbor took place, while some Americans believed that all Japanese people were spies or here to follow through with more bombing. I believe their fears were unjust simply because not everyone that is Japanese was a threat to America and they should not have been put into camps.

I hope this helps :3