I didn't take the 50 minutes to watch that video (yet). But I'd like to make a few points in defense of loners here. Because I've always been one at heart.
(btw. the below numbered points are not necessarily related to the 10 types of loners mentioned in the OP, it's just for easy reference.)
1 - Being an introvert is not the same as being afraid of people. I'm an introvert, but you can hardly call me afraid of speaking my mind, or of asking something when I'm looking for answers or help. Some people just don't see that much value in the social game, or maybe they just don't really like people all that much from up close. Who says they should? And who says they're wrong?
2 - I used to feel unworthy. Now I'm well over it. While that has eliminated my inconfidence, it has not changed my preferences about the social game. Being a loner is not the same as being awkward, shy, ill-adjusted or any such thing. In fact I consider psychological independence a key characteristic of a healthy and mature mind. Being alone is not the same as being lonely. And even if you are shy and awkward and insecure and whatnot, that doesn't mean that that's the reason you're a loner, unless you wish you weren't.
3 - There are other benefits to playing an MMO than the social game. For example a living breathing environment, or a realistic economy, or sensible interactions. Think about how much effort some single player games put into simulating that.
4 - What one calls commitment, another calls prison. You'll notice the word association there. Calling someone commitment-phobic is like calling someone prison-phobic and making them out to be the weird or flawed ones. But maybe different people just have different priorities or different values. Maybe browbeating someone into self-sacrifice for the collective is no better. Maybe it depends on who you ask. Maybe some prefer a Borg cube and others prefer a Firefly.
5 - Why treat "loners" as a wrong that needs to be set right, a mistake that needs to be corrected, or disease that needs to be cured? There are loners in the real world, why shouldn't there be loners in a virtual world? You may wonder why a loner would want to be in a virtual world (or in the real world for that matter), but there's a difference between being a loner and being 100% isolated. Very few people, including loners, want to be 100% isolated, even if only for pragmatic reasons. Also there is a very big difference between interacting when the situation calls for it, and playing the social game. Totally different things. Maybe some just enjoy being able to co-exist in peace without everyone inflicting themselves on everyone else.
6 - I agree that solo playing is a choice and a trade-off. There are upsides and downsides to either option, and whether you choose one or the other, in both cases you'll have to accept the implications. That's what choices are all about. Nobody builds a deathstar alone. Or who knows, maybe someone will! Just not because of any special privileges for solo players (nor any other players). There can't be any reasonable expectation that a single player can accomplish all the same things that a group of players can, and certainly not as easily or quickly.