Loathing one's own country: is it immature?

Some time ago I had a conversation with a teenage guy who held great feelings of hostility against his home country (the US). He could not believe that his foreign friends would want to live in the USA, because it was such a terrible place. He went on to talk about how stupid Americans are and how all other countries were better than the USA.

At the time, I tried to argue that the United States has just as many problems as other countries, but he wouldn’t listen, so I dropped the issue.

Unfortunately, I see a lot of this in people, especially young people. It may have reduced a little bit since Bush left office, but there is still a lot of hatred in some Americans to their own country and government. Criticizing the government is one thing; this is different.

My question to you all is this: is this hatred something that is related to being a brash, unruly youth? Or is it just as possible for mature, educated people to harbor such loathing?