There's a big difference between suggesting that some people may have inaccurate and unnecessary diagnoses and saying 'psychiatry is a bit of a con'.
I've seen both sides. 16 yrs working in acute mental health nursing and also suffering from depression and anxiety that would have undoubtedly led to my own suicide without antidepressant treatment (and believe me; in my not wanting to be ill and thinking that with all my mental health experience, qualifications and psychological and analytical skills I could 'sort myself out', I tried EVERYTHING else).
I have extensively researched medical literature from both traditional sources and the 'anti-psychiatry' movement. Neither perspective is without it's own agenda. My BSc honours dissertation included extensive research and analysis of mental illness in third world countries and 'mental illness' is just as prevalent in countries that have no concept of 'Psychiatry', we just differ in our views and treatment of such conditions.
You are grossly inaccurate to suggest all mental illness is 'outside of societal norms'. In fact, the diagnosis of psychosis actually specifies that beliefs HAVE TO BE outside of usual social, cultural and religious beliefs.
Not everyone in mental distress has a defined 'mental illness' not everyone from these groups need medication or would benefit from a traditional Psychiatric/Psychological treatment but to suggest it's 'all a con' just makes you look silly and ill-informed.
I've lost count of the people I've encountered in my career that have been well and stable on medication for many years and relapsed into acute illness after having read some nonsense like you're now repeating. Many 'religious' groups including scientology spout it.
It's the same shit that suggests ADHD or ASD are attributed to bad parenting. There are many, many MRI studies that demonstrate the science behind neurobiological disorders which include mental illnesses including schizophrenia and depression. Just because we can't offer a blood test to confirm it for 'unbelievers' doesn't mean it's not real. You could have a migraine today, there's no 'test' to confirm that but it doesn't mean you're talking bollocks.