Graham Greene tied mobsters with Catholicism, but Pinkie, his Catholic gangster, was only one of several gangsters in the book. I don't know if any of the others were Catholic. A lot of criminals in Greene's Britain were Catholic, because a lot of the urban lower classes were Catholic, but I doubt the mobsters were as preoccupied with theological questions as Greene or Pinkie were.
I notice that Peter Mullan played the dying mob boss in the television film mentioned at the beginning of the article. I assumed he was Irish. Actually, he's Scots, but one of those Catholic Scots of Irish ancestry, so in a sense, the television show was about a Catholic mobster. I also find out Mullan is a Marxist -- literally and self-professedly.
For good reason. In a criminal enterprise, everything depends on your knowing everything about the people you need to trust, so you don't recruit a police snitch. The way to do that is to recruit people who you have known all their lives, and whose every move has been the subject of gossip as they were growing up.
Then you make them shut up, and have everybody who knows them shut up about them to outsiders.
For good reason. In a criminal enterprise, everything depends on your knowing everything about the people you need to trust, so you don't recruit a police snitch. The way to do that is to recruit people who you have known all their lives, and whose every move has been the subject of gossip as they were growing up.
Then you make them shut up, and have everybody who knows them shut up about them to outsiders.