I'm afraid I don't follow your point, there. Are you suggesting that the concentration camps were originally just started for the purpose of segregation and that they moved to extermination? Because by the time of the Wansee Conference, as that wikipedia article states, the decision to kill 'undesirables' and 'the Jewish Question' had been in full swing for years. Action T4 started in 1939. Concentration camps started in 1937 and were used as forced labor camps first, it's true...but the ultimate goal was to work the people within to death. Dachau was opened in 1933 and people there were dying of overwork, disease and malnutrition long before the war began.
The Japanese Internment Camps in the US were illegal and deplorable. It is a national embarrassment that the US would not formally apologize for until 1988. But the motivations for them and the results of them were far, far different from those of the Nazi Concentration Camps. Like the Soviet Gulags (and one should note that the Soviet re-purposed some of the concentration camps for their own use), the camps were a place to put political prisoners and enemies of the regime for the express purpose of removing them from society and eventually eliminating them.
Read Mary Matsuda-Gruenwald's "Looking like the Enemy" for a good contrast of the two. Her family suffered like any family would suffer from internment...but they did not have their property seized. Her brother (along with other Nisei) served DURING World War II, recruited VOLUNTARILY FROM THE CAMPS. Many camp members were given special exclusions to go to college. Families were permitted to stay together. Was it horribly damaging to the people subjected to it? Yes. Did some people die while in the camps? Certainly.
But there is far more than a question of scale to show the differences between the two. Hermann Goering is hardly someone to quote on the matter; simultaneously being the highest-ranking official within the Nazi regime to personally sign death-camp orders and claiming he wasn't an anti-semite and didn't know anything about the camps until shown his own multiple signed orders at Nuremberg. Goering would say there was no difference...he was desperately casting around for a justification. Canada also interred their Japanese citizens...and afaik treated them worse than America did theirs.