Prove it. There is no evidence at all that the actions prevent anything that proper, constitutional and legal investigation would have done.
It also helped protecte the Japanese in America from vigilate action.
Oh, I see, so it is okay for the Government to swoop down, strip you of your liberty and property rights and park you and your family in a camp, when you've done absolutely nothing wrong, so long as they think it's for your own good?!?!? Wow. Better not let Hillary in on that little gem...
Those who wanted to be good citizens were allowed to do so.
What about those who were innocent, did nothing wrong, wanted to be left alone and who didn't want to be stripped of their rights as Americans and sent off to Manzanar?? They weren't allowed to do that, were they?
No reported cases of Japanese civilians committing sabotage in World War II. On the other hand, areas with large German and/or Italian populations suffered from industrial disasters that the government had to explain away to avoid panic.