I understand your point but the thread was started with a view to ask about Japanese Americans and not Japanese. If I wanted to ask about other nationals being imprisoned without trial I would have started a thread about it or mentioned it in the OP but I want to stay on track.
Makes sense to me, then. We had 80,000 "Japanese citizens by being born here" to Japenese citizen parents.
Of those some were dual citizenship and some were only US.
This may be of interest.
https://archive.org/stream/nationaldefensem29unit/nationaldefensem29unit_djvu.txt