Is it safe to include names of mafia organizations in your fiction or will they read your work and come after you?
Will they come after you? Very unlikely, but not impossible.
It's my reader who bothers criminal organizations, it's not me. My reader is what they don't want. The fact that, in this moment, we are talking about it, that all the newspapers talked about it, that books continue to be published, and that documentaries continue to come out is what they don't want; they don't want attention on themselves, on their names, and, above all, on their businesses.
Roberto Saviano on his book Gomorrah
Roberto Saviano writes fiction about existing mafia clans, about their criminal activities, and uses real names and real places. In addition, he has made numerous public statements against mafia.
If you don't feel the moral strength to follow his path, then keep it generic. You can refer to mafia naming conventions, but try to not use real facts or actual people names in your fiction.