There is a significant difference between an old, structured, indigenous and pervasive criminal subculture and just regular criminals that only share a place of origin and residence.
In Sardinia you have the latter.
As I posted earlier, the anomima sarda was the closest thing Sardinia ever had to something resembling a criminal “underworld”…and it wasn’t even organized.
Anything above petty criminality is run by mainland mobsters who might occasionally use local muscle.