[Gil]

I think the problem is in fact economic in it's root and the whole "racial" element is used as an escape goat or as a side argument to support their views. The general view (from their perspective) is that the north is germanic in character and looks while the south (namely Sicilly) is (some would say) more "mediterranean" and some even like to claim "arab".
The problem stems from the land use and development of the regions: while the north was always highly industrialised and with most population the south was rural and lacking in people and development.
Anyway, there are italians on Stirpes so I think they are better suited to talk about this.