The problem with the Mafias is not so much the killings, but the impoverishment and corrosion of everything they control.
Be careful, as always, but Italy isn't an especially dangerous place. Some regions have higher crime rates than others, but even then, I wouldn't worry too much about it.
The Greens happened to be in a bad place at a very bad time - late-80s/early-90s saw big changes in organized crime and political structures, with all the trouble that sourt of situation will inevitably bring. Things are nowhere as tense today. Unless you specifically head for the ghetto, the worst that can happen as a tourist is overpaying for taxis.
Edit to avoid misinterpretation and backlash: those are the 4 regions (out of 20) where the Mafias (Cosa Nostra, 'Ndrangheta, Camorra, Sacra Corona Unita) kill the most.
World by country level: https://upload.wikimedia.org/wikipedia/commons/7/76/Map_of_w... (Yes, Italy is safer than Canada or Australia)
Europe by regional level: https://ourworldindata.org/wp-content/uploads/2013/03/europe...
So yes, even in the few parts of Italy that aren't scoring perfect, the murder rate is as dangerous as visiting the french south east coast, or visiting Scotland, or even north Germany. Not exactly hell of earth.
[1] https://en.wikipedia.org/wiki/Crime_in_the_United_States
https://en.wikipedia.org/wiki/Via_D%27Amelio_bombing
https://en.wikipedia.org/wiki/Santo_Di_Matteo#Killing_of_son
Killing police officers, wives of judges, priests who speak up agains the Mafia, torturing the 11-year old son of a pentito for two years... Charming. This romanticized view really does make me angry. The Mafia are scum, they are lowlife despicable murderers. They're unreservedly wretchedly scum. They haven't a a moral code, they bring misery to others for their own benefit, and as such they aren't above any other scumbag criminal (like the 14-yo gangbanger you deride).
The post I replied suggested that Italy is not safe because of Mafia. Yeah, Salvatore Riina did go into terror to force the state to settle some 20+ years ago, but how many people not related to their business were killed vs mafiosi? Things happen. People fall out of their beds too. USA and other countries have their own problems.
My point was that Italy is to be considered dangerous for tourists because of the mafia. https://en.wikipedia.org/wiki/List_of_countries_by_intention...
I honestly think all the replies miss my point.
Or maybe you can take your chances.