That said, 'internment camp' sounds far too weak. From what I've read, every piece of property they couldn't carry was taken, and they were rounded up and forced to live in horse-stalls for the duration of the war. Every single family, as far as I know, had to not only suffer the indignity of being held without cause, but then had to rebuild from zero after the war. I can't think of a better term, but it needs one.
And "concentration camp" is itself a euphemism for "prison camp". So its probably better if we strip out the euphemisms and refer to:
1. "Prison camps", and
2. "Death camps" (or, even more accurately, "Extermination camps")
(Recognizing that the second is a subset of the first, not a disjoint category.)
And avoid "concentration camps" and "internment camps" entirely.
Concentration camps are where you send people to die.
I'm not sure what the distinction is you're trying to make. That calling them 'interment camps' is somehow better than 'concentration camps'? Both words refer to holding a designated group of people, perceived to be a threat against their will without evidence or trial.
"Concentration camp" implies something else entirely, to them.
"Internment Camp" is a euphemism for "concentration camp", which is itself a euphemism for "prison camp". "Concentration camp" has also come to be a euphemism for "extermination camp".
So:
Is a: | Can be called a [...] Camp
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Prison camp | Internment, Concentration
Prison camp with labor | Internment, Concentration, Labor
Extermination camp | Concentration, Extermination, Death
He is talking about the first line, you are talking about the third. In modern English, the term "concentration camp" is most strongly associated with the third.(Actually, IIRC some Japanese prison camps were in fact labor camps, though I think the work they did was almost entirely agricultural. No bomb-assembly to my knowledge.)
@dragonwriter suggests avoiding the terms "concentration" and "internment" entirely and only using "prison" and "extermination" (https://news.ycombinator.com/item?id=6260756). I think this is a reasonable suggestion.