Well there are a few places that I've been to that it is also looked on with some distain, not just the United States. It is like that in the United States because must likely the situation is that there is a deadbeat kid that just mooches off his family. In many other countries, the children work along side their parents in the same business or field of work, hence they are much closer because they wake up, work, and eat together. A false equivalent.
It happened in the 1950's. I can't explain all of the reasons, but suffice it to say that the nuclear family (parents and their children only) became emphasized and extended family were only people that came by for holidays. Some of it had to do with home-ownership being seen as this all-important entity. I think it has caused a lot of problems in American society.
On top of Gandalf's post, you always add the article when it's a descriptive. For example, "Il mio cane" describes the dog as yours, but "È il tuo cane? È mio" is used as an answer and not a direct descriptive (note how "tuo" had "il" in front of it because it was a direct descriptive for the dog).