1) his python script mixes up a bunch of social conditions, medical conditions, financial conditions and other things that are "bad" but having known several people on welfare, for example, actually being on welfare kicks the shit out of needing welfare and not getting it. Cognitive disability sucks, as does dementia, but not only are a lot of people who suffer from these maladies leading full and happy lives, they'd probably resent being lumped in with chronic drug users. Besides which, "am currently on probation" sucks a lot less than "am currently in prison" and "have ever been physically abused" says fuckall about where you are now.
2) 300m people in the United States, 29 million psychiatric visits in 2012 (pp 3). That's one visit per ten people. One can safely assume that patients under psychiatric care have more than one visit; assume they're having a visit a month (kind of a minimum) and you're under one patient in psychiatric care per 100 people, about the same percentage (according to him) as the number of people in prison, in nursing homes or schizophrenic.
3) So the people he's seeing are that sliver faction that are not only suffering maladies and can afford psychiatric care, they can afford psychiatric care and can't handle their lives. As one clinician in an office of 20, guaranteed he's seeing exactly the sort of people who reinforce his view of the world.
I used to hang with psychiatrists. They specialize like anybody else. One I knew dealt primarily with the worried well. Another dealt almost entirely with recent divorcees. The third dealt with prisoners and the homeless. Guess which one had the best stories? If you guessed the one with the bleakest outlook on humanity, give yourself a gold star.
According to his list, I'm two out of his 17 categories and right now? Right now I'm on top of the fuckin' world and it was a rugged goddamn year.
How bad are things? Well, for a lot of people they sure ain't good. But for a lot of people, their presence in one or more malady boxes doesn't dictate their existence the way it does for too many acolytes of the DSM.