This is a blanket statement that is untrue in my first-hand experience as a medical student. If you see a mistake is being made and can back up your opinion, you are treated with respect.
The problem is that medicine is very complicated and there are often not single 'correct' solutions. Given competing reasonable interpretations, the physician liable for the patient will (and should) make the final choice.
There is an alarming amount of anti-physician bias here. Physicians walk around like Gods? No, they walk around like people who generally have a very good clue and years of experience about what they are doing and are constantly attacked for issues outside of their control or completely outside of their patients' understanding, despite their best intentions and efforts.