Shitty situation but almost nothing that guy could have done. If the guy had retaliated, one (more likely, all) of the black guys filming would have jumped in and probably killed the guy.
However, all those girls should be rounded up, dropped into a meat grinder then used as fertilizer. If it was a bunch of white girls and that was some nerdy black guy, Al Sharpton and the Rev would be all over the airwaves calling for rioting in the streets. When drafting the Hate Crime laws, legislators should have explicitly included "unless you're White" since that's the case in all situations.