It'd be pretty hard to blame Kiu Fung if he had an abiding hatred of medical doctors.
First, when he was a child, a heartless doctor refused to treat Kiu's ailing adoptive father because the Kiu family was too poor to pay for medical services.
Second, Divine Healer Sit refused to help Ah Chu on the grounds that Kiu Fung brought her to him, and repeatedly insulted him as a Khitan dog.
You think maybe Kiu Fung had a hate-on for physicians in general?
It's too bad that Kiu Fung never met a doctor more like, say, Cheung Mo Gei.