I have probably spent 4+ hours a week, uncompensated, arguing with insurance "doctors" to get my patients standard of care. I would bet the suspect list is quite long but would bet on someone who has been denied life saving care in a purely profit motivated way.
United is one of the worst. AI will auto deny. I write a letter of medical necessity, get denied. Request "peer" to peer. For the record, I rarely talk to a doctor who has the same primary board as myself and I have never talked to someone who holds my subspecialty board. I try to embarrass them, shame them, make them feel they will personally get sued.
My favorite things to say: "Can I ask what you are boarded in so I know what level of explanation I need to use to talk about this rare disorder?" "Can I get your full name and NPI so I can be sure to accurately document in my medical record who is practicing medicine on my patient in case of lawsuit?" "As I am sure you and your company are aware of current literature, do you have a process of updating standards to be up to date with the 21st century of medicine?" "I am happy this is being recorded, and I do encourage you to release our conversation to the public to see who they side with."
One of my mentors in Cleveland would use the line "You are only denying care because this patient is black." I have not used that yet.