✔ 最佳答案
Its not a crime to be a member of a gang. In fact its protected by the fist admendment ("to peaceably assemble" AKA freedom of association). Its when they start commiting crimes or are present when a crime is commited that they're in trouble.
However dispite ones freedom of association, being a gang member will get you alot of unwanted attention by the police. Those kids on youtube constantly have to watch they're backs not only from rival gangs, but from police that are just looking for an excuse to arrest them.