We have prisons which are run by the government, and we have prisons which are run by private companies that sell their services to the government. Call the latter what you like. The companies that run them do a poor job with prisoner safety, and lobby the government to keep the prisoner supply high. In some cases states have signed contracts that require them to supply a minimum number of prisoners regardless of crime rates.
https://www.washingtonpost.com/posteverything/wp/2015/04/28/...
http://www.theguardian.com/commentisfree/2013/jun/13/aclu-la...