They’re technically not making treatment decisions, they’re making payment decisions about treatment decisions. Effectively it’s a distinction without a difference though. And it’s usually a “doctor” working for the healthcare company rubber stamping the denials. It’s a thoroughly shitty system.
Specifically, it’s the doctors who technically passed med school, but only just. They’re not going to practice medicine anywhere else, but they can make good money writing up legally protected reports that say “in my professional opinion, this patient’s lack of arms does not prevent him from going back to his roofing job”.