Either that or government-approved websites (like the NHS is providing in the UK). It is in the government's best interest to keep you alive for as long as possible (if nothing else, just so you can pay tax longer), and while they aren't always perfect (like the current covid-19 response from some countries) I would still trust them more than some random people playing doctors on social media.
> What would the mechanism for "eradicating" these "quack therapies" look like?
Outlawing unproven medical claims, and actually enforce the law?
> Well, can we really say big pharma isn't evil to some degree
Perfection will never be achieved, but if we take all the effects of "big pharma" (both good and bad, across all diseases) and compare it to the effects of backyard quack medicine, who wins? I'm willing to bet good money that big pharma wins by a large margin, so I'd be willing to trust them until there is enough evidence that says otherwise.