As recently as 2022 en masse convictions of corrections officers have been happening within states.
In Georgia during a two year sting 46 people were convicted, all DOC employees, mostly Corrections Officers.
Taking away physical mail from people already deprived of their rights seems extreme, especially when the problem pretty clearly is COs who enable it.
https://www.justice.gov/usao-md/pr/final-defendants-includin...
https://www.ajc.com/news/atlanta-news/court-overturns-guards...