I bring it up in response to the story because it's an obvious part of the narrative about Japanese internment camps in the U.S. in WWII that is suppressed because it is inconvenient and uncomfortable. That doesn't mean we should ignore it, though.
Obviously, this event makes the actions the U.S. government took look more justifiable. The fact that it happened so quickly after hostilities started is also striking. The idea that Japanese immigrants and Japanese-Americans are more likely to turn against their adopted country than, say, German or Italian immigrants seems more plausible in this light, and that helps understand the decisions made by people in power (in addition to stuff you already know, like Japanese is a very different language to English and culture to American, far more different than either German or Italian, and Japanese people and other East Asians are much more easily visually distinguished, etc.).
And, I will reiterate, in my mind it doesn't justify interning tens of thousands of citizens on the basis of ethnicity. It seems obviously wrong to me, either you're a citizen and you get the same rights as everyone else, or you're not. Discriminating on the basis of ethnicity is...racism? Not quite, but I suppose that's the word people use. It is a stain on the country's history.
On reflection, I think what really grinds my gears is that shaping the public consciousness with lies and half-truths is so effective...