MS13 are a different breed, if i remember correctly it's an EL Salvadorian prison gang that just spread like wild fire, it's a number of reasons for kids joining gangs, fear of the gangs, lack of family, the social structure of the environment, poverty, the need to be a part of something etc. Sometimes depending on the region or city kids can be pretty much born into a gang.
FYI, even the Crips or (Cribs) and the Bloods started out as community organizations or social clubs but along came the multi million dollar drug trade fueled by the CIA for the Contras and the supply of high powered weapons and everything changed look it up, (freeway Ricky Ross, Oliver North, CIA connection with inner cities and drugs) it's all there and no conspiracy theory.
Rap or so called gangster rappers are 0.1% of the problem, gangs existed long before Rap was invented and even then so called gangster rappers didn't appear until the 90's when big money came into play with the music scene. 50 is probably the worst example because those that know what he is about identify him more with being an incredible business man that stayed on the top of Forbes list making a killing with his investments especially ownership of Vitamin Water and Coca Cola's purchase of it (400 million for him), along with other business moves and his incredible marketing ability.
50 (Curtis Jackson) early music talked about his life as a hustler and being shot 9 times, his mother selling drugs and being murdered and the body burned but nothing about gangs (hustlers, crews and gang culture are different) his movie get rich or die trying was actually really good it was based on his life growing up a hustler.
Good to know... I never pay attention to 50 cause all I ever heard was how awesome he was for being shot and stabbed so many times.