The only thing is, with gangs like the camorra, and even cosa nostra, those boys grow up on the streets of naples or in backward provinces of sicily like agrigento, there is no work. So even the mothers groom their sons to be good soldiers and work like their fathers. You're born into your family, which most likely already has mafia ties and connected. So it's either you renounce it and get an education and look for any remedial job, sit on unemployment for years, or are lucky enough to get work, or you stick to your mob ties.
On the streets of those cities, you either eat or you're eaten.
But in the US, there is absolutely no reason for anyone to be involved, or actively try and join mafia.

And they're all part of a gang. Hence the word "gangsters". Some just more organized than others.