There was a popular (within the mob) myth that Albert Anastasia had some cronies cause the SS Normandie fire to "demonstrate" the need for a more cooperative relationship with the fellows who really controlled the docks.
From my understanding, the Sicilian mafia has been considerably more vicious and violent than the American mafia: entire families are considered fair game, as are a bunch of people who the American mafia would consider off-limits: Prosecutors, Judges, Police, Journalists (in the USA, killing one of them brings down the wrath of God Almighty and the Justice Department). There was a war between the different clans that broke out in the 1980s and the Italian govt. tried to crack down (the Maxi Trials). Magistrates, police and carabinieri personnel, and ordinary people became targets when the mafia clans responded with a terrorism campaign that spilled over into mainland Italy.
Ah, now we're cooking.
You are correct about the American Mob having very strict rules about killing civilians, politicians and police. They much preferred to bribe them, less heat. To quote Virgil Sollozo; they're businessmen, and blood is a big expense.
I have heard this story, but I am unsure it is true. Normandie seemingly was a true accident. However, it does give the FBI and OSS reason to approach Meyer Lansky - who is known to be hostile to the Nazis - for help controlling the docks. Lansky routinely sent Bugsy Segal and his Jewish henchmen to visit Nazi Bund meetings, which they dispersed violently and with great joy. Lansky says maybe they can help, but they need to move Lucky Luciano to a less secure prison closer to New York. Which is done. Luciano is finally released from prison, and expelled from the country, for his direct assistance helping Patton overrun Sicily using his Sicilian catspaws to show them the smugglers routes over goat trails and mountain passes unknown to the Germans.
Albert Anastasia is the man with the greatest nickname in the history of the Mafia: Lord High Executioner. The man who killed Joe Masseria - along with Vito Genovese and Bugsy Segal - for Luciano. He ran Murder Incorporated, and used the Jewish Mob controlled by Meyer Lansky as part of his murder-for-hire operation. You want to hit an Italian, you send in a Jew they'd never suspect to be a contract killer.