You guys couldn't have been much more than middle-middle with such a myopic understanding of cultural differences. It strongly suggests a lack of foreign travel, or exposure to foreign customs. You were correct until you mistakenly declared the idea that your social psychology is the "right" one.
Your proud self-identification as Italian instead of American, coupled with the rest of this post, sounds like your pops was hard working but blue collar.
My understanding is not the "right one", it is simply the ideology I care to follow and everyone else is free to do what they want. The thing is that I didn't make those rules or standards and neither did my parents. It seems like every other Italian and European family we interacted with stressed the same thing so I don't think my understanding is so myopic.
I've traveled all over Europe, Central America/Caribbean and a little bit of Asia and noticed the same thing in the cultures. If you eat like a bum or you hold your fork/chopsticks improperly, it reflects poorly on your background and upbringing. That may or may not be true but that is the opinion many people are going to form of you. I spent time with the Maya in Yucatan Mexico, Malay/Indians/Chinese in Singapore and many places in Europe and I found this to be one of the things they have in common. If you eat and look like a barbarian while doing it, people are going to notice it and form their opinions. It is even more strict in Asia, where if you file your chopsticks against one another as if you want to remove the splinters, that's an insult to your host. If you make noise with your chopsticks/plate, that's what beggars do to attract attention. You should never stick your chopsticks straight up in your food because that resembles some sort of incense burning ritual done at funerals. And etc etc etc... Perhaps America doesn't have these sorts of stringent rules. To us, they seem inconsequential, but it is the equivalent of smacking your lips or burping/farting at the dinner table.
My father is a proud self made business owner who is pretty independent and was educated in a Jesuit boarding school. Even today, he is in his 60s, he still eats the way the monks/sisters/priests instilled into him; elbows at certain angle, certain amount of fingers distance the chest should be from the table edge etc etc etc... Both my parents are conservative old school people from farming communities in Italy and expectedly so, have instilled in my sister and I the same rules/customs that they were brought up in. And I intend to do the same with my children.
I'm not trying to offend anyone here or appear stuckup or snobby. But someone mentioned that "white people" don't care how people appear when they eat and that is simply wrong. It all depends on what circle you come from, what appearance you care to give when in public and whether or not you care about such a thing.