the author of this article is several years late picking up on the philosophy of Seinfeld. Thomas Hibbs wrote a book, I believe, called "Nihilism in Popular Culture" which focused extensively on Seinfeld. Dr Hibbs visited my college 6 yrs ago and talked about this. He basically made the same points as this article does. The characters on Seinfeld embody the nihilist way of life. They care about nothing other than themselves; they mock family life, religion, and interpersonal relationships. In that sense they are not unlike many contemporary liberals. When I lurk on the DUmp, I see the same kind of mindset, only with far less humor than the characters on Seinfeld had.
That being said, Seinfeld was still a very funny show (most seasons, at least). I think anyone with an iota of sense could watch it, enjoy it, but also realize the characters were unpleasant people that one would not want to be like or be friends with. The show did a good job of not promoting nihilism by portraying the nihilist characters as unlikable folks who get into situations where things blow up in their faces in the end. This is actually better than many other sitcoms. There have been several other TV shows that promote the same "values" as Seinfeld did, but instead portrayed their nihilistic characters as likable, funny, happy people. "Friends" comes to mind. This kind of sitcom nihilism is far more insidious than Seinfeld's is.
Funny, I read a book on the same subject by Art Vandalay.