One of the biggest problems with the prison system in the US is that prisoners are often saddled with the debt related to or imposed on them by their incarceration which they can't pay back.

The inability to find a job coupled with the crushing interest is what leads to desperation, and then repeat criminal behavior.

> There is a real risk of exploitation

Centralized systems always have a risk of corruption when power is concentrated in few people. Those job roles also many times attract the corrupt; and even when you have people who go in with a good moral caliber, the regular dynamics of the interactions may also twist them into being corrupt.

Its a rare person with sufficient moral caliber that can survive such a job (as a guard or other prison staff) unscathed and still be a good person afterwards.

Many avenues of education also do not prepare them appropriately for work in the private sector, and some careers are simply prohibited. For example becoming a chemist or engineer when they have a conviction related to ethics violations in such fields.