Nurse Ratched wasn't particularly evil, she was just of ''the day''

She was just very connected to the system. And the system loathed the mentally and encouraged all its employees to treat these people as criminals and keep them caged (unfortunately, not that much has changed today).

Even the orderlies were also very disrespectful to the patients as the attitude (viewing mentally ill people as animals) had trickled down.

I hope you understand what I'm trying to say. This type of ''Nurse'' was about as common as bread and butter in psychiatric hospitals. Psychiatrists were even worse. Many referred to their job as like ''working in a zoo'' and admitted that they were a warehousing facility with throwaway people.