except as a punishment for crime

Those are explicitly for low level crimes. Normally considered 'community work sentences', they're forced unpaid volunteer work in the community that you would have caused harm in. Graffiti or Vandalism for example might have you work with local volunteer groups who go around cleaning up graffiti or repairing broken windows. Basically cleaning up the very thing you caused.

Yes. Slavery was abolished, except for people being punished for a crime: prisoners. That's why the private prison industry is so profitable.