Apparently that article about the unreliability of Doctor Oz et al. has prompted lots of people to say “well obviously you shouldn’t trust a doctor on some tv talk show!”
But it’s not obvious. It’s not obvious unless you already know it.
It’s not at all easy to know which authorities to trust, and it’s not obviously stupid to assume that people on tv are constrained by some sort of rules or standards about truth and competence. We may think it’s obvious, but I think if we do we’re forgetting that we have some background knowledge about Oprah’s attraction to woo and the like. Not everybody has the same background knowledge, to put it mildly. It’s not self-evident that Oprah likes woo, because Oprah is a very intelligent and skilled tv personality. She doesn’t come across as gullible at all; rather the contrary; that makes it all the harder to be wary of what she tells us and of the putative authorities she promotes.
This makes it all the more reprehensible that she does promote a woo-monger like Mehmet Oz. She has huge power to persuade people of things; she comes across as an authority to many people; therefore she should do a much better job of filtering her medical experts. With great power comes great responsibility yadda yadda – it’s a cliche but by god it’s true. She could have a reliable, evidence-based medical expert as a regular on her show, but instead she has Oz. Bad move.