I don't know what it's like in the US, but here it's very common to see job advertisements padded out with unnecessary and heavily loaded language like "we need a bubbly, bright and outgoing administrative assistant". I looked at a person spec the other day for a local council admin job which had "good sense of humour" in the desirable column. For that sort of job, personality type shouldn't come anywhere near the decision-making process - and whoever wrote that person spec should be called to account.
It's not outright discrimination, but it does come close - and the experience of the bloke in the article is something I can identify with. You send in a good CV, stellar references and an eloquent, articulate covering letter, get called in to interview... and come second because you're ever so slightly awkward and tend to prefer to concentrate on working rather than making small talk about Britain's Got Talent. Perhaps it's partly why so many hacker types end up gravitating towards the startup world rather than a job in some big company...
All technical positions require some social interaction. If the job is pure development, then I wouldn't worry if someone is a little socially awkward. I would worry, however, if they seem very awkward. People aren't hired on pure ability alone, and I don't see anything wrong with that. One of the most important questions an interviewer can ask themselves about an applicant is "Do I want to work with this person every day?"
Even some technical positions require significant interaction with non-technical people, and in those cases, it's reasonable to expect some who is sociable.