Unfortunately that is demonstrably not the case. There are many qualified, experienced, doctors who are happy to peddle nonsense. Even limiting yourself to conventional medicine it's hard to tell the effective medication from the less effective medication.
> What right does anyone have to deprive anyone else of what might be their only shot at life?
What right does anyone have to manipulate desperate dying people out of vast amounts of money on unregulated, useless, gambling?
I'd agree if you're suggesting that people should be able to volunteer for trials - but double blinding means they may not be getting the experimental treatment.