Next time you need major heart surgery, feel free to jump on a plane to Naples. Good luck with that. And all of the medical breakthroughs coming out of Sicily...
Been in plenty of Italian hospitals - but you clicked on Wikipedia so....
Your position is anedoctal, the WHO rating is fact based.
But, it is true that Sicily and Naples (Campania) could do much better, as this picture shows:
This just means that the North health care system must be even better to bring the overall system so high in WHO rankings... and that is the system (in Piemonte, Emilia Romagna, Lombardy) that is overwhelmed right now.
Sicily and Naples have been barely touched by COVID-19 (for now).