Citizens in various countries have been wrongly punished harshly for their ethnicity. Democratic countries have been no exception in meting out inhuman treatment to their own citizens. Thus, who is enemy is at times simply a perception and all laws of the land are set aside in democratic countries. Concentration camps are the proof of failure of great countries.
India
Most of us Indians are probably not aware that Independent India has had a concentration camp with untold sufferings. Yes, they were human beings like us and innocents.
Indian Chinese were tortured and harassed by the Indian government during the Sino-Indian War in 1962. Property of many were looted by the public.
It may sound unbelievable, but many were taken to the border and pushed across to China even though most had never been to the country. Such ethnic cleansing-like measures instilled fear in the community. That fear ultimately triggered an exodus and many migrated to other countries.
The victims were arrested (in Assam, Kolkata and other parts of India) and bundled on to Deoli in Rajasthan by goods train. Many families got divided as they were sent in batches. Some died on the way. Some spent over four years behind barbed-wire fences patrolled by soldiers whose rifles were always pointed at them.
It is estimated that approximately 3,000 men, women and children of Chinese descent—most of them Indian citizens—were imprisoned in Deoli without trial. They were simply picked up on the pretext that they posed a threat to India’s security. Evidence cited against them was the color of their skin and facial features !
Some in the Government had doubts on the detention.  Union home minister Lal Bahadur Shastri gave the detainees a clean chit in 1963 ! He told Parliament that no one would be tried for spying or subversion. Nobody was prosecuted.  They lived behind barbed wires like POWs for four years.
USA During WW 2
 Italians, Germans  and Japanese origin people were detained without trial  in USA during World War 2.
Between 1942 and 1945, thousands of Japanese Americans were, regardless of U.S. citizenship, required to evacuate their homes and businesses and move to remote war relocation and internment camps run by the U.S. Government
Located in remote, desolate, inhospitable areas, the camps were prison-like, with barbed wire borders and armed guards in watchtowers. Families were separated.
American citizens of German and Italian descent also received similar treatment. Some were even deported to “their” country which they hardly knew !
It is ironical that while the allies were liberating concentration camps in Germany, they were building the same in their own territory !
Britisher’s in Africa
In 1900 (long before WW 2), the  Britishers put civilian enemies in concentration camps in Africa. The victims were Dutch settlers during the Boer war. All this was for plunder of Diamonds and Gold of Africa.
After defeating the Dutch they put them in concentration camps. These were overcrowded. It is estimated that about 25,000 women and children died because of disease.
Thus concentration camps are not synonymous with Germany.
Recent influx of Syrian refugees to Europe and inhuman treatment being meted out to them should make us wonder- to whom does the earth belong ? Are we any different from those  in stone age- might is right.
If one has muscle (fire) power one can draw a line anywhere and claim that area of earth as his! So much for calling ourselves civilized.