I assume you're referring to the technicality that the thirteenth amendment allows unpaid labor to be legally compelled out of prisoners, and that's a valid thing to be outraged about, but your statement is wildly misleading to anyone who isn't already aware of that technicality.

The existence of the loophole is terrible and should be amended, but it's nowhere near the humanitarian crisis that widespread chattel slavery was. Ironically that will probably make it that much harder to be fixed since it's more difficult to draw pubic outage towards it.