Clients?
Call them what the IRS calls taxpayers: “customers”. (It’s true!)
We mostly called them inmates as far back as I remember. The doctors and nurses called them patients. The SAP (substance abuse program) instructors called them clients, but I didn't know that, until two instructors came to my cell block, and told me they needed to see some clients. I said, clients? You mean inmates?
The most PC thing I saw, was when they changed the department from CDC to CDCR. That was PC.