You know how carefully she chose that word. She's fully aware of the ramifications of using that language (I suspect she's probably one of the very few people who read "The Gulag Archipelago" cover to cover).
(There's lots of stuff up on her site, but right now I can't get anything to play. Maybe just my old OS and browser. Maybe try https://www.ms.now/rachel-maddow/watch/trump-hits-a-wall-as-americans-get-wise-to-his-immigration-prison-camp-plans-2484977731947 later).
And yes, it's time for US citizens to start asking ourselves how we would fare in a concentration camp. These camps may be "intended" for immigrants, but as Rachel says, "It they build it, they will fill it." Trmp referred to reporters as "enemies of the people" years ago, and now it seems like almost anyone who disagrees with him in any way is now given that label. *Some* of our press are finally starting to notice how out-of-control Trmp is, but will it be enough, soon enough ?
***ETA: see https://www.democraticunderground.com/132165731*** for link to Rachel's show