So... immigration services in the US don't use criminal language when discussing how they handle people accused of immigration offenses, because there's a whole legal structure to pretending it's a civil infraction and thus you don't have any rights related to say... trial by jury or the state proving your guilt beyond a reasonable doubt.

But. The mechanical processes can include indefinite detention in facilities that look and function exactly like jails.

So... what you CALL it is almost certainly something different than what it is.