And if anyone is wondering how this is legal (yes, it is 100% legal), I hereby direct them to the US Constitution, 13th Amendment, Section 1,
Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.
In other words, slavery or involuntary servitude is fair game if you've been convicted of a crime.
Which is very fucked-up in my opinion. "Land of the Free", my ass...