Most of the folks here on HN are dealing with customer feedback in systems automation in one form or another - it's pretty unavoidable in this age of LLM trendiness. The customers of healthcare (in both private and publicly funded systems) are the patients. So while the term might not be super natural it's an understandable one to use.
Patients are not customers, or at least I don’t want to live in a world where patients are considered customers. Customers and vendors are usually more of a symmetric relationship: price transparency, alternatives, lack of urgency. These are all characteristics of transactions that healthcare often lacks.