The program that led to a very small percentage of German nationals in the US and an even smaller percentage of German Americans in the internment camps was for German nationals that were considered to be pro-Axis. They did not mass intern German nationals, let alone German Americans. German Americans that ended up in these camps generally went voluntarily to avoid family separation. There were a lot of Nazi sympathizers in the US at the time and it's not surprising that a small percentage of German nationals may have been supportive of the Nazis in ways that were considered problematic.

Japanese internment isn't considered problematic because it led to Japanese nationals that were supporting the Japanese war efforts being interned. It's problematic because it was indiscriminate and race-based - nearly all Japanese Americans in the continental US ended in internment camps. There's no comparison here - Japanese Americans were treated substantially worse than even German nationals, actual citizens of the country the US was at war with.

> You also forget that in Japan the Emperor was a cult-like hero. The majority would have walked over a cliff for him.

I'm struggling to find a charitable interpretation for this. Could you elaborate? Are you saying that it's okay to consider Americans of national origin X traitors if the US is at war with X and the country X happens to be led by a cult-like hero?