While I agree that avoiding quackery is the right thing to do one mustn't forget that some of the current science-based medicine is actually harmful.
One classic example is cholesterol and statins. Low cholesterol actually increases your risk of dying.
The diet approach to cancer did wonders for the late Steve Jobs.
If "allowed an easily treatable early form advance to an aggressive fatal case" is "did wonders".
It has always amazed me how people can quickly dismiss people of science who have studied and researched for thousands and thousands of hours but will quickly adapt any quack theory with no basis in fact.