what does the discussion about McMurphy's diagnosis tell the reader about the possible abuses in mental hospitals?

The irony is that McMurphy was not even mentally ill. He had various charges against him like street brawls and barroom fights, repeated gambling, and even one arrest for rape. It isn't until McMurphy is in the institution that he becomes mentally unstable. It is an indictment of Nurse Ratched and the system. It is a system takes mentally healthy men, like McMurphy, and makes them worse than before they came in.