I don't think the "Italian" food you can find here is from the South. Now that you make me think about it:
- Raviolis, they are typical of Piemonte and Emilia Romagna
- Linguinis, fettucinis, lasagnas and fresh pasta is typical of Emilia Romagna
- Fainà, that's typical of Liguria (farinata) and can be found only in the area surrounding Genova, to be precise (including part of Alto Monferrato, which belongs to Piedmont)
- Fugazzeta, that comes from the ligurian "fugassa" (focaccia in plain Italian) and it is a Ligurian specialty.
- Tiramisù, that's from Veneto, in the North East.
- Pasta frolla, I don't know where it comes from, I'd say it is very similar to french pastry, so I am inclined to think it came from the North
- Pan dulce, that's a typical Christmas sweet made in Liguria.
- Pizza, yes, that originated in the South but I believe by the end of the 1800's it was widespread as pasta
- Parmigiana di melanzane, yes that's from the South
- Milanesa, that's from Lombardy or from Austria. There is a dispute on the origin of the plate, but don't forget that Milan, the Lombardy and Veneto were ruled by the Austrian for 50 years. Anyway, definitely not a plate from the South.
Where you thinking about something in particular? I think the hot blood is a very Latin trait, which South Italians, Spaniards and Northern African have in common. Don't forget that in the Mediterranean sea there was a lot of mix up of the centuries, Arabs coming to Sicily, Spain and Southern Italy, and backwards (esp. during the Roman empire). I can't really understand the hatred of Italians toward North African immigrants - some of them are physically identical!
I don't know who "imported" corruption first... it looks like the Roman society was already pretty corrupt, but I am no history buff.
About politicians in Argentina, Macri (I think it was originally Macrì, the accent got lost somehow) and the others, most of the Italian immigrants of the 1900's were from Calabria and Sicilia, so I don't see anything particularly alarming about so many people with Southern surnames in politics.
I looked up the surnames you mentioned and
Franco is prevalent in Piedmont-Liguria,
Francella is equally present in Lazio and Marche, Lanusse is not Italian, Macrì is of course Calabrian. About the handshake with "Palabra de calabrese" (in Spanish), I find pretty sad that italo-something really need to go back to their ancestor country to find some common ground, and that most of them rely on (negative) stereotypes. When I see restaurants called "Il Padrino" or "Corleone" with signs evoking the mafia movies, I don't know if they want to make fool of the non-Italians who "buy" into this sort of thing or if they themselves believe that's the height of Italianism.
On a side note: nobody affiliated with mafia would open a restaurant called "Il Padrino", so I am inclined to believe it is just marketing for people who don't know any better than them.
I personally don't identify with Southern Italian, and all of these italo-something initiatives found in BsAs are by and for people from there. Two block from here in San Isidro there is a Sardinian association that sing and dances to Sardinian songs in dialect... They invited me to join to make me feel home... but that's very VERY far from my Italian experience. And I don't know many people from the South of Italy who would identify themselves with these things nowadays. I remember reading about an Italian girl in Buenos Aires who said she rarely hangs out with italo-argentinians because they are stuck to weird stereotypes of Italians that get old very quick. I can't agree more.