My argument is that it's not an "epidemic of depression" that we're dealing with but rather an "epidemic of over-diagnosis". I would argue that the industry is in practice being far too loose with the definition of "significant impact on one's lives". I think articles like this one blur the line even further by making it sound like everyone who has experienced a few of these symptoms suffers from depression. People read stuff like this and then start telling themselves "I'm depressed" and because of this mistaken belief many of them wind up being medicated inappropriately.
This epidemic of over-diagnosis has reached such vast proportions that I imagine the majority of people in the tech industry have been prescribed some kind of psychotropic drug to treat some form of mental illness at some point in their life. I wish I could get accurate statistics on this to prove my point.
As a side note I do think that caffeine induced psychosis is 100% real (because it's a very powerful drug) and the symptoms often mimic that of depression or bi-polar and can even be inclusive of phenomena such as hallucination. I don't have any credentials but my opinion as a layperson is that I think it's incredibly irresponsible to write a prescription or to give a diagnosis for any mental illness to a patient who has not first completely cut caffeine out of their lives.
Some conditions are overdiagnosed, and there is a too-cozy relationship between medicine and pharma that is disturbing to many of us.
However, to make a diagnosis based on Diagnostic and Statistical Manual (DSM) criteria almost without exception (one exception is for bipolar II disorder) require that symptoms (and several symptoms are required usually for any given disorder) must cause significant impact on one's lives, eg,
"...sufficiently severe to cause marked impairment in social or occupational functioning or to necessitate hospitalization to prevent harm to self or others, or there are psychotic features."
or
"...symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning."
EDIT: (based on your own edit) - reserving diagnosis and treatment just to those at risk for self- or other-harm is going to harm many suffering people. I don't think you understand what depression really is. It's not caffeine withdrawal or the flu. Even when no suicidal ideation is present, it's a serious disease with real costs to the individual and to society, just as real as cancer.
Beyond depression, I think you'd agree that even in the absence of harmful behavior or ideation, people who experience auditory hallucinations in the course of depression, or OCD sufferers who are unable to work because they must wash their hands hundreds of times a day, or who have PTSD triggered simply by backfiring engines, or who have dozens of other DSM diagnoses, all have legitimate illnesses that deserve much more than the terrible, stigmatizing suggestion that their illnesses somehow are not real.