Sorry, but this feels like a lot of weasel lawyer doublespeak nonsense. Denying insurance coverage for a specific procedure for a specific patient based on whether you think that procedure is necessary is absolutely making a specific medical decision that will impact the treatment of that patient. The idea that this does not constitute practicing medicine is absurd and the fact that the patient can potentially still obtain treatment seems immaterial. A doctor who flat out told a patient a certain procedure wasn't medically necessary could be legally liable if that wasn't accurate, so how is the same not true of an insurance company who has far more impact on the ability of the patient to obtain treatment?

The reality is that this is the insurance companies trying to have their cake and eat it too. They actually want to be making a medical decision in denying coverage since it gives them a legitimate reason to do so, but want to avoid any liability if that decision was wrong.