@Wolfcub Having watched all the episodes (it was a highly addictive show!) I felt that it changed tenor partway through and I'll be interested to hear if you felt the same after you're done. The first couple of episodes were straight up mysteries that needed solving- people with defied diseases, but just so rare that many docs hadn't seen them before and then could not recognize what they had never seen. Happens to many of us when confronted with something new and strange.
But about partway through the show switched to people and problems that didn't fit any established paradigm, no matter how rare. In this land there are no clear cut answers and no definite answer to the question "Why?, Why am I sick?" Because the honest answer is that medical science just hasn't progressed far enough to tell us. This is where it transitioned to diagnostically grasping at straws and venturing into the land of the "functional". This is where unspoken assumptions about causality come out.
If medicine at one point believed that all disease originated in the body, it has just rediscovered the mind-body connection, and is now transitioning to thinking unexplained disease originate in the mind. (I'm not talking about mental health here. Psych diseases are very real, very painful, and still not the patient's fault.) Obviously the mind and body are connected in subtle and complex ways and are not at all well understood. We don't even know if the mind is a product of the brain, the CNS, the CNS and other parts, the body as a whole, or an emergent property. Extrapolating from this lack of knowledge to a functional or BPS paradigm for disease causation is problematic. Not least because these explanations are inherently patient blaming (If you'd only managed your stress or dealt with your trauma...) but because these explanations blind their proponents to the fact they are patient blaming. This is what I find most infuriatingly frustrating. But it's in this realm of diagnostic uncertainty that these unacknowledged and unconscious biases come out.
And come out they do in Diagnosis, as soon as it wanders into this confusing and vexed territory. Honestly, I think this is where most of medicine is going to live, so we'd better develop a better roadmap than BPS and functional explanations. They're about as effective as drilling a whole in your head to let out the evil spirits.