"So You Giving Me A Lecture About Not Being A Good Enough Gangbanger?"
Most people's friends and family would try to stop them from getting involved with gangs. Franklin's world is different. In one scene, his best friend Lamar and his Aunt are on his case because he has not been participating in gang activity.
Clinton uses the quote in question to point out how ridiculous their complaints are. Especially as his Aunt claims that his mother would be rolling in her grave because he has moved away from gang life.