Maybe something got garbled somewhere... Comparing ICE detention centers to concentration camps is clearly absurd, but comparing them to US internment camps [0] doesn't seem so far-fetched to me. Note that the Wikipedia article calls these "concentration camps" in the opening paragraph, so I'm not even sure it's fair to automatically assume "concentration camp" implies "Nazi death camp".
[0]: https://en.wikipedia.org/wiki/Internment_of_Japanese_America...