If you'll note, I made specific observations in subsequent posts about my own life and the one time that I found myself without a social network or the tools to build one in the community I lived in. I didn't lack a social network because I was depressed. I lacked a social network because I had little or no common interests or experiences with the rest of the community.
Furthermore, I firm believe (from observation) that shy people are much more apt to wind up lonely and depressed than extroverted people. It's so constant that I can't see anyone actually refuting it.
I worked with a very polished, outgoing man. We got to talking once about medical things, and he told me he had been hospitalized for anxiety attacks. Never in a million years would I have ever thought that. For me to be surprised just shows that I was judging a book by its cover. Sounds like you do the same thing.
With regard to your presentation of your depression.... it's like someone who had a sprained ankle criticizing someone with a broken ankle. "I was able to walk through it, and only needed a day or two off of it. You're malingering."
Your "shy" reasoning is completely opposite of those I know with Depression. EVERYONE I know (and quite a few in my family) with depression is more of a type A personality. They DEMAND they be heard almost to the point of rudeness, talk incessantly and can be very overbearing. They are sometimes the MOST fun people to be around but can also "turn" on a dime. They aren't big on "socializing" with friends, but when they ARE around they are the center of attention. It's an odd mix of traits and sometimes hard to nail down.
One of my best friends suffers from depression but you would NEVER know it as she's hilariously funny and loud. When people find out that she has a depression problem, they are always shocked.