Well, multi-player is where the money is right now, so that is of course what most companies are going to want to defend at the moment.
One also has to remember that with all the masses being brought into gaming, the guys who want to be interconnected by things like Twitter and Facebook, serious gamers, many of whom are the solitary "geek" types are now a minority within the hobby.
I disagree with this guy, but I do understand where he's coming from. Personally I like both kinds of games, for the most part I prefer single player experiences though because to be honest other people being involed frequently ruins immersion or inevitably leads to them being obnoxious. As fun as MMOs and such can be, a time inevitably comes when I feel my brain cells melting listening to other people talk or chat, and just need to get away to do my gaming elsewhere.
In the end though, the lowest human denominator that has been brought into gaming represents the most profit, and does outnumber the more serious gamers. Catering to them, and being able to sell say virtual shirts and such to people to show off to each other is a big business. Few companies can resist the temptation to chase after the biggest profits possible, what's good for gaming itself, espcially in the long term, be damned. Companies will always try and find some way to justify their actions and position, including doing things like spouting banality over how single player is a gimmick.