Don't be so sure.  Look what happened to Japanese citizens in the US during
World War II.  If you're prepared to say "Let's round these people up and
stick them in a concentration camp without trial", it's only a short step to
gassing them without trial.  After all, it seems that the Nazis originally
only intended to imprison the Jews; the Final Solution was dreamt up partly
because they couldn't afford to run the camps because of the devastation
caused by Goering's Total War.  Those who weren't gassed generally died of
malnutrition or disease.