First and foremost, you're incurring in a slippery slope. Do you want reality, as complex as it may be, or merely to win an argument? Second, you don't see it

First and foremost, you're incurring in a slippery slope. Do you want reality, as complex as it may be, or merely to win an argument? Second, you don't see it because you don't care for their problem, otherwise you'd either learn what the actual hard scientific research on the topic by neurologists and psychiatrists show, as well as the measurable results of the different clinical protocols developed by psychiatrists and psychologists, or defer to their expertize. You yourself "not seeing why" what they do in such cases is what needs done is as meaningless as you "not seeing why" any expert does what they do in fields you're not yourself an expert in. So either become one, or stop getting in their way based on "common sense"-based cognitive errors and biases.