I appreciate your asking and as a person who also suffers from SAD I hope I can give a little insight.
I have written this type of post before (not on here, but elsewhere) and it was done more for myself than any individual reader. It's cathartic. Those of us with SAD don't have a person we can 'say' things to in our lives. Heck, even the thought of saying things out loud and face-to-face to someone can be beyond frightening and paralyzing to many. So we write. It's 'safer'. We can post it out there and never look back at it if we choose. I commend Gary for even coming back and posting/replying in the thread. That can't have been easy.
For those who do not understand this disorder they often offer advice such as; "just make friends", "put yourself out there", etc. It isn't that easy for us. Depending on where the disorder stems from just following that type of advice can be physically dangerous (I have a few scars that can attest to that). Might I suggest reading up on Social Anxiety Disorder, NIMH has one of the better information sheets that answers many of the common questions. Knowledge is power they say.
Personally, I loved what he wrote and related very much so to the telling of his story. My path has been very similar so I was able to read the post with compassion and connection. When I got to the end I felt that what he wrote was a "Thank You" to ANet and GW as a whole for a life he had enjoyed within the game. For the lessons he has learned thru the game and how they have helped him outside the game. He then stated what changed for him in the game and why. Again, that was something I could relate to and was more directed to ANet (i.e the story direction/twist) than the community as a whole I believe.
I hope that this helped you understand a bit more than you did. Thank You, again, for asking for enlightenment.