I'm not sure what your point is. This discussion is about medical researchers making decisions on thousands or millions of patients in aggregate... what you're describing is a common thing (don't know how bad a tumor is until it's removed).
The doctor didn't know that before removing the tumor (almost certainly; the alternative is medical fraud).
Doctors going into uber salesman mode selling dangerous surgery is super common. So very common among heart surgeons it’s comical. Point is, blindly trusting doctors and their judgements will in all likelihood just turn you into a sickly perma patient.