Okay I'm gonna try to paraphrase this as best as I can;

From my experience-- and the experience of many, many members of neurodivergent/marginalized communities-- psychiatry is largely based off of the medical model of disability, which necessitates clear, precise definitions of mental illness in order to provide a functional diagnosis.

Many, if not all, of these definitions are entirely based on the patient's own symptoms. The problem arises that patients need to provide a personal account of their own symptoms, and many people don't have the necessary knowledge base to define and describe their symptoms accurately.