They join for the same reasons any other person on this planet joins a criminal organization: easy money for people who don't have much prospect in regular life + not having to work a shitty job or be unemployed. It was the same decades ago and it will always be like that, in every society you'll have criminals.

It's not like rich kids are joining the mafia instead of going to college because of some movie or "charm", people who end up in the mob were mostly involved with crime since they were young and have nothing to lose.