The fact is, in the wake of Pearl Harbor there WAS immense resentment, even hatred in many cases of good loyal Japanese-Americans, and with a war on, it was not possible to post an armed guard with every one of their families, so while there may not have been a dire threat to our national security from real (or imagined) Japanese-American agents-in-place who might have committed acts of sabotage/espionage, it was WAR and whether right or wrong, FDR believed it best to ship them off to those internment camps, and it remains to be seen (and remains open to speculation) IF those Japanese-Americans would have been safe from the righteous anger of Americans who had been sucker punched at Pearl Harbor.
If you want to look for ‘black stains’ I could recommend some things far more reprehensible.
If you think Americans of Japanese descent needed to be stripped of their liberty to protect them from white Americans, then you don’t have a terribly high opinion of white Americans. That’s a shame.
It was not about “protecting” them, no matter how leftists might want to spin it today. It was a panicky and racist decision that they couldn’t be trusted. And they were wrong - Japanese-Americans were highly decorated when we let them out of the camps and in to the Army.