You are Mediterranean. Also your ancestors are. That's the truest nature of an Italian. Coming from the Mediterranean sea that means: Culture, politics, different concept of State, philosophy quite different from the north-Europeans, another concept of living and use of resources (agronomy or another concept of materials) and the best important thing of all: Roman law.
Yes you are right. Probably an Italian from the north is not the same from another one from the south. But you are come from the same roots. I guess that negative concept of Naples is due to how Austria was in the north of Italy. These kind of countries have the bad custom of classifying everything and everybody in ethnics, cultures, races, etc... So this is the reason why they inculcated that thought of Naples or southern Italy.

We're all the negro of someone — Olivier5

And yet so many 'passers' are in deep denial of that fact.

And yet so many 'passers' are in deep denial of that fact. — 180 Proof

Traveling helps, being exposed to other forms of prejudice than the one at home, which we tend to internalize and be blind to. When I lived in the US, I realized that over there the Catholics were the underdog. There's quite some thick prejudice about them in America, whereas in France, Catholics tend to treat Protestants as the underdog.

There's a whole philosophical travelogue literature about the virtues of being exposed to other societies for seeing your own society in a new light.

:up:

Traveling helps, being exposed to other forms of prejudice than the one at home, which we tend to internalize and be blind to. — Olivier5

I expect you are right. I've been exposed to very little cultural variety. I shock myself sometimes when my internalized attitudes come out unexpectedly.

I shock myself sometimes when my internalized attitudes come out unexpectedly. — bert1

Me too actually... Better become aware of a prejudice than remain unaware though.