A psychiatrist relies on therapists, somewhat similar to how physicians in other specialties rely on lab technicians. Yes, all diagnoses are guesses.

Of course you don't have to go to medical school to be educated. But that is pretty much what it takes to be competent to make medical diagnoses. Does that mean that nobody but a physician ever made a correct assessment of what was wrong with someone? Of course not.

There's an old saying about a little knowledge being a dangerous thing.

It's not true that you have to know what's wrong with someone to be able to treat them. Sometimes, it is through treating someone that a doctor is able to discover the diagnosis. Lots of times, initial diagnoses prove wrong. You don't really treat a diagnosis; you treat symptoms. A lot of symptoms are apparent to any observer.

One of the reasons psychiatrists don't spend a load of time with patients is because their main job is to prescribe drugs to treat symptoms. That is pretty much an empirical process. They throw stuff up against a wall to see what sticks.

Therapists attempt to motivate changes in behavior. That's another way of trying to relieve symptoms. Therapists, nurses, techs and even friends and family are typically in a better position to observe behavior than are psychiatrists. Of course, the pdoc needs their input.

There is a reason why the SSA does not approve an application for psych disability based on the opinions of therapists.

Once in a while a nurse figures out what's wrong with a patient before a doctor does. That doesn't mean that nurses are qualified to diagnose. It's not what they are trained to be responsible for. Therapists are trained to interact with clients in a therapeutic way to interrupt dysfunctional thinking and promote healthily adaptive behavior. They don't really need a diagnosis to do that.

I am not dismissing master's level clinical therapists as being uneducated. But they are not educated as diagnosticians, any more than nurses are. That is not their wheelhouse. Their professional development is to fit them to interact therapeutically with their clients. Lots of doctors aren't even particularly good at interacting with patients. Each profession has its role to play.

For reasons I can guess at, but not be entirely sure of, we've got nurse practitioners and therapists out there who are in over their heads handing out diagnoses. Oh yeah, they've taken entire classes on differential diagnoses. That's way short of what it takes to train a diagnostician.

If you suddenly get severe abdominal pain that you've never had before, do not go to an urgent care center to be seen by a nurse practitioner. Go to an Emergency room and get seen by a physician. If you want help in coming up with a plan to manage your life better, see a therapist. If you absolutely have to have a diagnosis, see a psychiatrist. Most psychiatrists will want to hold off on the diagnosis, until after they have treated you for a while. In an in-patient setting, insurance tends to want, at least, a prelimary diagnosis fairly quickly. Physicians tend to come up with the diagnosis that will justify the admission. Pdocs and E.D. physicians do this quite readily. The purpose of the diagnosis is to enable everyone to get paid. It really doesn't have all that much to do with determining treatment.

BTW, pdocs often don't really know what's wrong with their patients.

Labels don't help you understand "what you are working with." Working with people might eventually help you understand what label is applicable.