When they ended slavery they explicitly carved out an exemption for prisoners who could still legally be enslaved. These prisoners are by and large majority minority and are often used by the state to enrich themselves. EG its a huge cost to the country but a given county where a prison is situated gets a lot of the money so spent, prison guard unions earn money from their members, everyone working in the industry makes money, companies are able to make money from cheap labor, in some cases private prison companies are directly enriched.

In response to this said parties lobby heavily for more enslavement. This is often accomplished by over policing minorities especially for drug related offenses, turning the penal system deliberately into slide into interested parties pockets instead of a ladder up, setting policy with an eye to increasing costs as opposed to benefiting society.

In at least a few cases judges were literally caught selling children into slavery. In exchange for kickbacks from a private prison company they were sentencing offenders to maximum sentences.

The bad thing is that were someone unjustly enslaved merely for the color of their skin we should all rush to break their chains. Someone enslaved by a system which shook them down in hopes of finding drugs and then ruined their lives there is no sympathy because they are the villain. America never ended slavery they just found a way to justify it.