Oh I completely agree that the practice is messed up. Some of the hardest workers I have ever met in my decade plus at Target, were deaf and/or slightly autistic.There are certain circumstances where you can do that, it's called supported employment.
It dates back to the days when rather than do real rehab they would stick people with disabilities in broom factories.
There are even companies that pay people with disabilities in gift cards.
It is a horrible, dated concept and fuck anyone who does it.
On the positive side
Federal contractors have to pay the federal minimum wage.
Alaska, California and two other states have made the practice illegal.