I would like to explain a few things to our American friends.

Until the arrival of television, was more spoken the dialect, that the Italian because Italy was still an agricultural country. In 1961 there was a television program that was called Non è mai troppo tardi (it's never too late) which taught to read and write in Italian.

the hate and prejudice against all southerners, was born after the unification of Italy in 1861, when the kingdom of Sardinia annettete the Kingdom of the Two Sicilies, then all industries in the south were destroyed, and there was a pervasive misery.

so was born the myth of southern born criminal

"It is to the African and Oriental elements and (excepts the Greeks), that Italy must fundamentally, the greater frequency of murders in Calabria, Sicily and Sardinia, where the lowest is where predominated the Nordic races (Lombardia)." so Cesare Lombroso wrote in his main work, The Man delinquent in 1876.
"Italy is composed of two dissimilar races , with physical and psychological character entirely different; one of these races populate the north and the center, the other the south and the islands. "
So wrote, however, the Sicilian Alfredo Niceforo in 1898.

then the prejudice has always been against all southerners.

Now over time it is likely that people of Naples insults those of Palermo. But it is indifferent and those who say that Sicily was invaded and raped by several people, I want to say is that was the whole Italy.

As an example, when I went on summer study holidays , I saw some Calabrians that teased the Sicilians saying that the cartel "Welcome to Italy" stay at a villa san giovanni, while in messina there is a cartel "Welcome to Africa".

I could do other examples, but I hope I was clear, just because some asshole insults a sicilian, doesn't mean that all the Italians hate Sicilians.