We reviled the Germans and the Japanese in WWII for a lot of reasons, one of which was their use of slave labor to fuel their war machine. Today, the U.S. military depends heavily on prison labor to acquire its materiel.
The moment society says "Hey! Let's make a little money off prisoners" it gives certain unscrupulous individuals the clever idea to FIND ways to put people in jail, and it's clear this is already happening. Our prison population should NEVER be used for commercial purposes.