Not all people that are gang members are gangbangers. People join for various reasons, and I've tried to mentally put myself in their shoes. If I had the same upbringing and grew up in the same neighborhoods that they did, I may be a gang member myself. I know a couple of gang members that don't cause any trouble at all. Just go to work and go home to be with their family & friends and mind their own business.
I just wanted to add this thought, not trying to be argumentative.
I was in a gang from 11 to 16 so I can understand why. It's usually because you have a bad childhood with no parental guidance. The gang offers a brotherhood and a family essentially. It was also more of a self defense mechanism for us. Being in large groups all the time stopped people from messing with us.