[roenxi]

But you didn't build my house, and if I literally get angry with you because I think you should abandon your legal shenanigans, admit to being a builder and take on legal liability for the flaws in my house that would confuse you because you are, in fact, probably not a builder and certainly not the person who built my house.

The issue with teeray's original comment is that they are saying someone who isn't practising medicine should be considered to be a medical practitioner. In fact, in this context, teeray is annoyed with them specifically because they didn't practice anything. Your analogy became irrelevant the moment it involved you doing anything.

> “X is or is not medically necessary” seems like a decision a medical professional should determine, no?

No, that is ridiculous. If I think I need to go to a hospital I'm going to go to the hospital. I don't need qualifications to work out something is medically necessary. I'm unlikely to be involved with the medical industry at all unless I've already personally determined it is medically necessary that I consult a doctor.

As a rule of thumb, patients have the final word on what they actually consider necessary. Literally anyone can have an opinion on the subject. Like, for example, an insurance worker. If the patient or the doctor is of a different opinion then they can go pay for the work themselves. It isn't that uncommon to have to go through 3 or 4 medical professionals to find one who agrees that work is necessary; I have a cancer story like that in my family.