It's an illustration of a majoritarian government power grab. I certainly do not object to condemnations of Japanese internment camps! They were one of the biggest mistakes our country ever made. I object to the root cause analysis you've performed on it, and because this is a thread that is almost entirely about that root cause analysis (and not Japanese internment), I think that's a germane criticism.

The President has broad powers to direct the military to take action. Telling the military what to do is a power uniquely within the President's purview. Telling the military to round up a group of people falls squarely within that power.

That's not a legitimization of the situation--you can argue that Japanese internment was illegal for other reasons, but we're not talking about the legality of Japanese internment in general. We're talking about the executive usurping powers reserved to Congress.