This wouldn’t normally be a subject of skepticism but current events have led to some common misunderstandings that we hope to clear up. Some evidence of concentration camps has been found in Roman ruins near Hadrian's Wall. It is still under debate whether these were refugee camps or concentration camps and we’ll never know until time travel is invented. The modern concentration camps date back to the Boer War in South Africa and were first used by Kitchener. This was the first time camps of this type were called concentration camps but camps of this nature predate it.
During the relocation of Native Americans by Andrew Jackson, the Native people were forced into improvised camps as they were forced off their land. People were deprived of sanitation and consequently disease was rampant, causing the death of thousand in the camps and on the journey they made afterwards that became known as the “Trail of Tears”. This treatment was emulated by the Spanish General Weyler in his treatment of people on the island of Cuba during their independence war in 1897. These examples predate the coining of the term 'concentration camps' but describe similar if not identical conditions. Concentration camps were used extensively in the British Empire following their success in Boer War. They were even used on the British isles during both the First and Second World Wars. People who were German and Italian were forced to live in camps on the Isle of Man, some Scottish islands and the mainland. Similarly Japanese Americans were concentrated into camps in the Californian desert, George Takei (played Mr Sulu in Star Trek) was interred there as a child. These were sanitary compared with camps in the Empire but people were still deprived their liberty simply because of their ethnicity.
The most infamous use of concentration camps was the use during the Second World War by Nazi Germany. The first camps were set up almost immediately after the Nazi's came to power in 1932 to hold and torture political opponents and union organizers, and very soon any 'undesirable' including Jews, homosexuals and other minorities. Many of these camps later became or were associated with 'death camps', which were designed to systematically murder the inmates on an industrial scale. This is the association most people make with the term and explains why people have such an emotional response to the term. The words "concentration camp" however refers to a concentration of people based on ethnicity or other arbitrary grouping forced into a camp. This is an accurate description of the camps created by the Trump administration's policies on immigration (and legal asylum) currently in the US, and in the camps housing a suspected 1 million Uyghur Muslims in China. People have been shitty to people throughout history and still are. Arguing about linguistics doesn't stop the human rights violations from happening.