Good question; I can't read the author's mind since the quote is made up. But basic logic dictates that the quote (which is apocryphal) means that we cannot de

Good question; I can't read the author's mind since the quote is made up. But basic logic dictates that the quote (which is apocryphal) means that we cannot deduce that we are healthy simply because we are well-adjusted to society, if that society is sick. It does not say that psychiatric illness is rooted in societal or social problems. And empirically, proponents of the quote (theosophists and Buddhists) also rarely use it to refer to actual psychiatric illness, but rather to moral compasses, values, and overall behavior. I doubt you'll find many Buddhists parrot the "I'm only depressed because of how messed up society is" line that you often see on the web, since Buddhism explicitly preaches self-transformation.