Yes, I've heard the same sort of argument over here in the US. Also, "Italian-American" cuisine is largely of Sicilian and southern Italian origin - e.g. pizza and putting oregano on everything. The Mafia stereotypes also fit it with Sicily, but of course we do recognize that not all Italians are mobsters. I think it's both a pop-culture thing as well as an after-effect of the migration patterns.
The major argument that I've heard regarding why Italian-Americans predominantly migrated from southern Italy is an economic one - that the southern part of Italy was more economically depressed during the periods of peak migration and thus triggered a greater "let's get out of here" attitude. By comparison, many people in the north thought "Emigrate to America? Why? We have it pretty good right here."
I don't actually think the data supports that, although I'm aware that's the trope about Italian immigration current in the U.S . There were certainly particular factors in southern Italy which propelled emigration, such as the fact that most of the farmland was owned by large landowners or the Church, which meant that there was a huge number of landless farm workers, ecological destruction to the land, a sudden population expansion, etc., but there was a lot of poverty in some areas of the north as well, especially the northeast, ie. the Veneto, which hemorrhaged emigrants.
The center fared rather better because of the land practice known as mezzadria, where peasants farmed land owned by landlords in return for half the harvests. The landlords paid for seeds, equipment etc from their half of the proceeds. A good number of men who didn't have such a contract simply didn't marry and merely provided labor on the farms of their relatives, as did various sisters/aunts etc. It was common in my mother's area. Parts of Lombardia, my father's Apennines mountains, some of the mountain areas of northwest Toscana, etc. were also pretty poor.
In the first burst of immigration, prior to 1900, there were actually more immigrants from the north than from the south. Then, southern Italians start to form a larger proportion of the emigrants, making it about half and half. After World War I, the data I've seen shows southerners formed a larger proportion of the numbers. There's also a difference in destination. Much more of the northern Italian immigration went to countries in continental Europe (from which people often returned), and then to Latin America, to countries like Argentina and Brazil. The present Pope is a descendent of immigrants from Piemonte. The closest non 'actual family' DNA relatives on 23andme with whom I'm in contact are all from Argentina. (They were treated terribly in the early years in Brazil, by the way, but that's another story.) Perhaps because they migrated to other Romance speaking, southern European founded countries, these diaspora Italians seem to have retained their ties to Italian language, culture etc. far more than have Italian Americans.
That isn't to say that southern Italians didn't go to Latin America, it's just that a lot of northern Italians went as well. Instead, in the U.S., the vast, vast majority of the Italian immigrants were from southern Italy and Sicily. The few northern Italians who came to the U.S. often came in the earlier periods, and a good number of those went to California and out west.
It also has to be kept in mind that the first choice for emigration after the earliest years was within Italy to the Genova/Torino/Milano triangle, which is still a destination for southern Italians. This is because this was the first area in Italy to industrialize, and because of the ports. We even got quite a few people from the Veneto and Lombardia in my area of Liguria, mainly because of the port of LaSpezia.
There is an English wiki article on the Italian diaspora, but like many wiki articles it's not very good, with many holes in its analysis. Some of these articles obviously have been changed to support various agendas. It's really too bad.
http://en.wikipedia.org/wiki/Italian_diaspora
This is one of the better graphics I've seen showing Italian emigration numbers. Of course, the data may not be exact, because records were badly kept.
It only covers up to 1915. There was a lot of emigration after 1915 up to the second World War, and then a burst after that, with much of it coming from the more southern parts of the country.
This article also seems to be rather well done and reputable, and it was done through the University of Torino.
http://ftp.iza.org/dp938.pdf
As to the "concept" of Italy, if you mention Italy to people here they might think "The Godfather" and the mafia, but I believe they also think food, wine, Rome, Florence, Venice, art, music, Pavarotti, film, warm family relationships etc. At least that has been my experience. Also, it has to be admitted that there are some Italian-Americans who seem to take an, in my opinion, perverse sort of pride in these criminals, just as there are some non-Italian Americans who seem to be fascinated by them. I find it inexplicable, but there you have it.
I also have to say that when, as recently, I'm in a group of Americans from places other than the northeast, or the west coast, or large cities like Chicago, where they are more familiar with Italian-Americans, and I mention in response to a question about my surname, as I did, that I am Italian born, I am quite showered with appreciative comments, ecstatic memories of trips there, or, conversely, requests for travel tips, and everyone seems to ask for food tips etc. It is all overwhelmingly positive. Italian members should not think that the opinions posted on racist anthrofora sites are at all representative of American attitudes.