First off, the Vagos aren't a Hispanic biker gang.
Second, it could just as easily be a bunch of tweekers, too. Meth is huge in the IE (Inland Empire) and up around Lancaster/Lake Los Angeles, and the Vagos make and push it.
A co-worker of mine when I lived there was a biker. One of the toughest guys I knew and even he wouldn't deal with the Vagos--claimed they were worse than the Hell's Angels. Between the Vagos, Hell's Angels, and Mongols, it's hardly any wonder motorcycle clubs tend to have a bad name.