This is a prime example of an over-correction where the general trend was in assuming that mental illness was "all in the head" (i.e., within one's complete control), also a scientifically inaccurate position. The extremist's response to this trend was the equally wrong claim that one has no control over mental illness. Now instead of blaming people for their mental illness, we excuse them for it—a response that lets the person wallow in victimization, rather than a response that empowers the person to get better.
Uncomfortable Idea: We should not treat mental illness like physical illness.

First, let's be clear that science and the medical community see all illness as physical in that the mind is a product of the brain, and if something is wrong with the mind, there must be a physical component to the illness. Some mental illnesses have recognizable physical components and some have no recognizable physical components. Some mental illnesses can only be cured or treated through changing the way the person thinks whereas others can only be cured or treated through surgical or chemical intervention—if even treatable. Given these nuances, we can say that telling someone with schizophrenia to "just act normal" is like telling someone with food poisoning to "stop feeling sick." However, when it comes to a vast majority of the most common mental illnesses such as depression, anxiety, addiction, substance abuse, eating disorders, and others, we have quite a bit of mental control over them as demonstrated by the effects of cognitive behavioral therapy (CBT) on patients with these illnesses (Hofmann, Asnaani, Vonk, Sawyer, & Fang, 2012). Many of these are labeled as "mental illnesses" for insurance reasons rather than scientific ones (i.e., thanks to being categorized as "mental disorders," help with such issues are often covered by one's insurance). Another example of how we bend reality for the good of the public.

We know enough about the placebo effect to understand how important the power of belief is and how it can have a significant impact on our physical well-being, not just our psychological well-being. If we start selling the public the false idea that mental illness is out of their control, we are doing a disservice to all of those suffering from mental illnesses where mental effort can mean the difference between life and death.

{apa}References
Hofmann, S. G., Asnaani, A., Vonk, I. J. J., Sawyer, A. T., & Fang, A. (2012). The Efficacy of Cognitive Behavioral Therapy: A Review of Meta-analyses. Cognitive Therapy and Research, 36(5), 427–440. https://doi.org/10.1007/s10608-012-9476-1
Holmes, L. (2014, November 13). What If People Treated Physical Illness Like Mental Illness? Huffington Post. Retrieved from http://www.huffingtonpost.com/2014/11/13/mental-illness-physical-i_n_6145156.html{/apa}