You seem to have a mental model where listening to an expert is the only possible way to distinguish whether to do A or B. That's not true.
An alternative would be what Kant called Enlightment. It's interesting that the idea of Enlightment seems so absurd as to be unthinkable.
Okay, so which method would you recommend to an average patient instead?
Listening to experts is the (imperfect) solution for a society with division of labor, so that most people don't have to study medicine and statistics and make their own experiments. General education can make you dismiss the most obvious nonsense, but beyond that you need an expertise, and either you spend years to develop it yourself, or you outsource it to other people.
John Ioannidis has written a very insightful and entertaining article about the current state of the movement which calls itself "Evidence-Based Medicine". The paper is available ahead of print at http://www.jclinepi.com/article/S0895-4356(16)00147-5/pdf.
As far as I can tell there is currently no paywall, that may change later, send me an e-mail if you are unable to access it.
Retractionwatch interviews John about the paper here: http://retractionwatch.com/2016/03/16/evidence-based-medicine-has-been-hijacked-a-confession-from-john-ioannidis/
(Full disclosure: John Ioannidis is a co-director of the Meta-Research Innovation Center at Stanford (METRICS), where I am an employee. I am posting this not in an effort to promote METRICS, but because I believe the links will be of interest to the community)