You're so right about that. I've heard a very alarming statistics about surgeries that were performed based on positive exams that turned to be false alarms. Something like half thyroid gland surgeries are based on false alarms. Mammograms are another thing that causes a lot of unnecessary procedures. Dr. Greger talks about this in this post: https://nutritionfacts.org/video/the-pros-and-cons-of-mammograms/
Another thing, how about all the over prescribed drugs and their terrible side effects? I was prescribed Prozac once a few years ago and I swear to God it gave me IBS. Besides, I almost harmed myself and the doctor kept saying that this was part of my condition. Later on I've found out that this is actually a very common side effect of the drug. Doctors have no clue on what they are prescribing to their pacientes.