Agreed, and it's not a matter of pulling oneself up by one's bootstraps or putting on a smile. It's a chemical imbalance and we cannot control it 99% of the time.
Well... I actually think that a lot of the older (and newer) theories the semi-pseudo-science called psychology created have contributed a lot to additional harm in the way we think and act about mood disorders in particular, and mental health in general.
Psychoanalysis and its spawns, along with some of the more sane ones as well are, at their essence, flights of fancy based on empiric observation
without any basis in hypothesis testing.
Research in brain physiology, on the other hand, although quite enlightening to some extent, is still in its infancy because we lack the more general tools of truly modeling certain highly complex systems.
So, while some therapies work, almost incidentally, they also misplace the focus by utilizing strictly unreal mechanisms of disease and explanations of phenomena; at the same time, neuroscience can explain quite a lot of basic phenomena and even behavior to some extent, but fails at understanding how these functional "building blocks" ultimately generate our actual longer term consciousness - thoughts, wishes, beliefs, values, and "self". Increasingly, it is quite depressing, though, to learn that, in fact, all these are from a certain perspective, illusions generated by resonating loopback circuitry so to say...
What I'm trying to say is that we are dealing at the same time with more and less than "chemical imbalances". Our brains evolved from movement control apparatuses, and gained all other functions quite haphazardly. They were never meant to deal with navigating one's destiny.
My personal understanding is that depression, at its most basic, is a protection mechanism to avoid unnecessary movement and energy expenditure in the face of conditions that prevent the performance of a certain action. It kicks in inadequately in our abstract lives just like anxiety. That, at it's most basic, is a mechanism to prime us in the face of emerging need for swift movement - fight or flight. It is obvious that rapid heart beats, dilated blood vessels and high sugar (meant to prepare muscles for maximum efficiency) and increased sweating (in preparation for additional heat to be removed) and hyperalertness (meant to prevent us from falling asleep and to help react quickly to attacks) do nothing to help the poor student in dealing with his Psychology test, but all these happen. Just the same with depression and learned helplessness following real or perceived constant mismatch between results and expectations in areas nowadays much more complex than ability to move in one direction...
Anyway, whatever...