There is a second truth that people miss--an inner calling/voice that "is what it is" as well. When this is in alignment with the way things are, things go well. But when things get out of alignment, when we are forced to chose (temporarily at least) between being true to ourselves or accepting things as they are, that's when spiritual pain sets in.
This is where we are tested spiritually. In many ways, we are simply talking around each other. I thing most of us are aware of the points people bring up. We cannot discount the role of heredity, biology in all of this.
Focus, I suppose, is the main point. We can of course find the silver-lining where there are gray clouds. But, often, it is simply wiser to bring an umbrella.
This is the hardest part (finding the right environment). The part most professionals, friends, family members, etc. are usually unable to do (and find very frustrating). IMO, this has to be done by the depressed people themselves, once they have regained the energy and resources to search.