I don't know if I am quite clear at what they are bitching about. Do they not want grieving to be included in a diagnosis of a depressive disorder? Because as someone who had a very traumatic experience with the death of a parent, I definitely thing grief/grieving SHOULD be included in that diagnosis. God knows the only reason I didn't off myself after my mom died was 1) I had my own daughter to care for and 2) I was on antidepressants.
While I agree that people process grief very differently, it can most definitely lead to severe depressive episodes. And some people are more inclined to depressive episodes than others, especially those who have had previous bouts of mental illness (anxiety, depression, etc.) I would think a prolonged period of grieving would be a really good indicator of a depressive disorder.