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".
ICE detention centers are closer to prisons than they are to nazi death camps. Calling ICE detention centers concentration camps is just pushing the "Trump is a nazi/Orange man bad" concept to its illogical conclusion.
