If your point was external actors of a hostile environment potentially reinforcing the cognitive distortions of a depressed person, rather than a healthy person developing major depressive disorder solely from disparaging comments, then I agree.
I don't think that it's made very clear, though.
And I don't see why it would necessarily keep depression from lifting regardless of the subject's own thoughts.

What I meant was that depression (major depressive disorder) does not equal anger, sadness and shame.
Though it does involve them to some extent, depression is something different than a combination of these emotions.

Yes - I straightforwardly dismiss what you wrote. No concession, sorry.
There are plenty of sources in my response to your google-search, but I'll summarize:

First of all: environmental factors are not the same as external causal agents or events.
They may be anything from triggering scenarios to contributing factors (such as childhood trauma, disease, pollution, malnutrition and drug abuse).

The American Psychological Association [0], the American National Institute of Mental Health [1] , the University of Maryland's patient education article [2], and Saveanu and Nemeroff's paper "Etiology of depression: genetic and environmental factors" [3] (all results from the google search you linked) describe major depressive disorder and its causes (as they are currently understood). They describe an interplay of various factors (see biopsychosocial and diathesis-stress models), but none of them mention anything about it being a response to external events in the way that "normal"/healthy emotions are - which is what I'm getting at in previous comments.
My point here is that major depressive disorder isn't something that spontaneously arises from a difficult circumstance.
Feel free to correct me if I'm wrong here, though I'd prefer some sources.

There is, however, something which is sometimes called reactive or situational depression - adjustment disorder - which is not the same as major depressive disorder.

The fact that you think you knew that I was wrong holds no meaning here, as you are basically claiming to be right (surprise) - and you have yet to prove your point, e.g. reference an authoritative definition that supports your case - which should be no problem if what you "know" is indeed knowledge.

Even if you had been right, a link to a google search wouldn't prove your point any more than a search for "vaccines cause autism" would prove Jenny McCarthy's "point". Not to mention that the results from the link did not back up your claims, as far as I could tell.

I never claimed that you owed me anything. I merely presented my opinion on why participants in discussions regarding mental illness (amongst other subjects) should take caution, as people's opinions and perceptions of mental illnesses have practical consequences, and so the usual no standard opinion-spouting carries a greater risk in this context.
This is no cognitive distortion, and if I were to use the same poor understanding and low standard of classifying these, I could claim that your allegation is a cognitive distortion itself - number 5 on the same list.

[0]: http://www.apa.org/helpcenter/understanding-depression.aspx

[1]: http://www.nimh.nih.gov/health/publications/depression/index...

[2]: http://umm.edu/health/medical/reports/articles/depression

[3]: http://www.ncbi.nlm.nih.gov/pubmed/22370490