My impression is that the question in the thread has to do with social harmony and the absence of violent crime within a country or region, and just what factors may promore or work against it.
It isn't evident to me that the confinement of Japanese Americans and Canadians on the West coast was indeed a violent crime at all. There may well have been some injustice involved, but that is a different thing. Clearly fear, whether justified in our contemporary eyes or not, was the real motivation for the action - that's easy to verify from contemporary public statements and news reports. I doubt that it was racism, in that neither we nor the Canadians rounded up our Chinese immigrants who were equally subject to any racism that is supposed to have existed.
I think Ceili's question involves lots of complications. There are numerous examples in history of otherwise well-ordered and crime free, apparently peaceful states that violently (and sometimes repeatedly) turned on racial, political or religious sub groups in fairly sudden ways. There are other examples of supposed exemplary states that were relatively free of crime and violence at home, but which readilly turned to it in foreign or colonial ventures ( Concentration Camps - involving most of the starvation and horrors of other familiar ones - were the invention of the British during the Boer War). Did the qualities that promoted the former peace suddenly vanish with respect to a despised sub group, or at the border with respect to foreign ventures ?
Clearly high degrees of social cohesion, cultural & religious uniformity and public acceptance of law are factors that enhance the peaceful situation ceili describes and are usually (but not always) associated with it. Likewise, cultural diversity and competition between identifiable groups and deficiencies in uniform public acceptance of law are associated (but not always) with violence. Interestingly, in apparent contradiction to all that, there are a few examples of highly uniformn monolithic cultural groups that actively foster traditions involving lots of internal crime and violence.
To me the crime was not rounding this communty up in WW2 but in not making them whole as must as possible after the war.
There is no excuse to had waited until most of them had pass away and then give the survivors token payments.