It's a silly rule that serves no practical purpose.
Think about it....the Russian OC groups have guys from mixed ethnic backgrounds and the Russian OC groups are a lot more successful than Cosa Nostra.
Look at Joe Watts who had a Welsh father and a Italian mother and he could have easily have been a Gambino capo had he been made. Watts bought in tons of money for the Gambinos but because his father was Welsh suddenly he is unworthy.
Stupid.
Please bear in mind that any organized group or street gang is by nature territorial. It could originate in a small village in Italy or a small city block in south Boston of Irish decent. It could consist of family members, ethnicity or friends. Usually it forms in impoverished areas. It's success can depends on many factors such as numbers, street smarts, power,ability to expand and other. The groups or gangs that are most likely to succeed are the ones that abide by their criminal code.
The Mafia being one of the oldest criminal group has proven itself time after time to be resilient & strict adherence to it's code. In Italy they do not have a recruiting problem,so naturally they will be more discriminate and will recruit usually from territories they control or originate from and family members. So in Italy, just being Italian does not guarantee you membership. Let's forward to the Mafia in the USA. In the earlier days with a large influx of Italian coming into the country there was no problem with recruiting Italians that originate from their hometown (Sicily) or southern Italy.
Accepting members based on origin is a practice that most criminal groups around the world follow. Are there exceptions ? Yes there are. Even though a non Italian is not a member, he can still be an important associate within the mafia organization. Especially, if they are good earners.
So I do not buy this idea that non Italians are not accepted into the mafia organization. Example,Mayer Lansky couldn't care less that he couldn't be a boss in the mafia, his standing in the Mafia organization as an associate gave him more power & money than most that were members.
