Technically, the Japanese internment camps we had in America were concentration camps, and there wasn't any gassing of Japanese Americans in there. But people were being detained against their will, which fits that definition. So, yeah. We technically have concentration camps.
Honestly, the comic does a better job of just how shitty a situation this puts people who are just doing their jobs in, because they have to enforce a shitty policy that does inhumane shit like this, and people are fleeing Mexico to get to the United States because fucking drug cartels are decapitating people and leaving their heads in the streets. I cannot pretend to know where to even start on fixing the situation with illegal border crossings, but this policy is so toxic, even Trump had to back off of it and try and deflect blame onto the Democrats for some exceptional-ass reason.
This is just an ugly situation any way you look at it.