It's not just Italy. All southern European countries have big numbers of unemployed people, who aren't actively seeking a job. Spain and Greece also have this problem. I'm not sure about Portugal or the Balkan countries, though.
This is what you get, when you combine a generous "welfare state" and not-so-attractive minimum wages. Many people don't find a valid reason to get a job and waste their lives working hard for a minimum wage(while staying poor).
Southern European culture adds something to the situation. Being hardworking and discipline isn't cherished in the South. The people prefer having a good time, rather than wasting too much energy on dumb activities like working in a 9/5 job.
I think it’s also about, that in Southern European countries the state established a framework that just works against the working individual and favors the corrupt and well connected.
You have a combination of broken economic incentives, weak property rights(which makes it hard to build companies etc., the state can just take your belongings without real justice systems), low mobility of the population(good luck moving around Italy when you’re poor, the highway tolls are huge), educated population moving to other places like Germany, and the list goes on.
While in Northern European countries the state tries to enable the individual to do better. Free university, high mobility of the population, strong property rights, strong minimum wages, better economic incentives, the state protects their industries instead of working against them. Northern Europe is for sure no paradise, but much better in this regard.
And the result of that is that the people in the south stop trying or move to other places like Germany and thrive there.
In the statistic i would also take into account that Italy made vaccination mandatory for workers over 50 years old, otherwise they can’t show up to their workplace. It’s a nice example of a state working against the individual, and destroying their own economy in the process. Even tho i think they took it back now, but depending on how much covid tests cost, it could also be that people can’t afford to go to work.
Idk which of these laws are still into effect, because they change every 5 minutes, but they definitely influenced the statistic.