The term "concentration camp" did not originate during World War II. It originated during the Boer War in the early 20th century, when the British Empire rounded up the Boer people (the descendants of the Dutch colonists) in South Africa and forcibly "concentrated" the Dutch population in refugee camps.
The British concentration camps in South Africa were not meant as extermination centers; the British did not intend to slaughter their Dutch prisoners. Yet over 100,000 Dutch civilians were imprisoned in the British camps, along with 25,000 Dutch-aligned Black Africans, and within the first year alone, 30,000 of them - many of whom were children - perished due to starvation, disease, and exposure. In total, roughly 12% of Black African inmates and 25% of Dutch inmates - including over 50% of Dutch children - died in the camps.
This wasn't because the British deliberately sought to mistreat their prisoners, but simply because they imprisoned vastly more people than they could reasonably afford to take care of. To the British Command, "the life or death of the 154,000 Boer and African civilians in the camps rated as an abysmally low priority" compared to accomplishing their economic and military objectives. At some point, deliberate negligence and gross incompetence become indistinguishable from outright malice.
So when people claim that ICE detention centers aren't really concentration camps because they're not Nazi-style death camps, that just shows that they don't understand what "concentration camp" actually means.