I would have helped the guy, but I'm 6'9", 300lbs. Would the thought of a gun give me pause? Yep. Especially since he's black (call me a racist or whatever, I call it playing the odds). But I'd have gone straight for the knee and then beat on him furiously until he was either a) unconscious, or b) restrained by the other guys there so that he couldn't get to any gun he might have.
I had a friend that was jumped by a bunch of guys at a party just because he walked into the wrong house on accident and immediately left. They were all black and took it as an insult ("Oh, because we're black you don't want to come to our party?!") so they beat him up. A friend of mine that knew the guy that was beat up since CHILDHOOD just stood there an watched him get beat (mind you, I wasn't there). Granted I'm big, but this guy lifts A LOT and is quite strong. He just stood there while his good friend was beat up. Sad.
Back to the original story, had I stepped in and beat the man unconscious, I wouldn't have been doing it out of hate or racism but because I don't know what kind of weapon ANYONE has, so I've got to make sure that the two of us that just want to order pizza in peace can go about our business. That piece of sh1t would have filed charges and the media would have made the whole thing into the next Rodney King. Jesse Jackson would have been there within the hour organizing a protest and I'd end up guilty of 2nd degree assault, all because I didn't want the innocent guy to get beat down and I didn't want the bigger guy to beat on me. Furthermore, then my name is placed on TV and everyone at my work and in my community that's black questions me and my motives. That creates problems for me in MY life.
Bottom line: I would have stepped in to help him, and I would have been more messed up than the guy who gets 4 years in jail.