Depression is a common problem, and it is natural that people should discuss it, especially from a moral view-point, joesbucks suggested on this thread. There is nothing evil about it.
I would have thought it more disconcerting if the forum received such tragic news about a member, but had nothing to say in response to the situation. Also, remember that many forum members have first-hand experience themselves and their families, of self-harm, addiction, depression, mental illness, and suicide. You may not know who they are, but they are there, so they do have insights and a right to comment, once an issue is in the public arena.
My point was, this poster's moments of self-doubt don't even begin to compare with the long-term depression my husband had.
It's like someone posting about a FReeper dying of pneumonia and someone posting a thread piggybacking on it saying, "I had the common cold once..."
It's insensitive and it's avoiding the issue and so are you.