Maybe it is hard to say something concrete because our minds are so complex and constantly changing? Plus, there's not really any concrete facts behind psychology, right? It's a bunch of opinions and theories?
So these "doctors" are basically feeling around in the dark?
They must maintain some ambiguity to protect their professionalism, how confident they look, and how much we trust them lol..
What if they were like "Well **** if I know what's wrong with you! You seem like a person to me!"
Then what? They'd lose a customer man!