This thread is the first I've heard about the incident. A couple thoughts...
First of all, the notion that this is punk rock and it's all part of punk culture is absurd. Afroman is about as punk rock and my aunt Sabra. The girl who got punched was no mosh pit animal either. This article -
Afroman Arrested After Punching Fan Onstage - tries to compare the assault to other cases of celebrity musicians and singers hitting fans, but this is not much like those. The girl didn't rush the stage, didn't grope or grab at him, nothing like that. She got up to dance and no one stopped her, that's all.
Second, the statement from him and his people is that the punch was an "involuntary reflex" caused by the girl's startling him with an invasion of his personal space, and by unspecified "outside uncontrolled forces." They should probably go looking up the definition of "involuntary" and "reflex." Nobody punches someone as an actual involuntary reflex. What they mean is that he didn't think before acting, which is no excuse. I'm sure the "outside uncontrolled forces" were probably pharmaceutical in nature.
They also say that he was on edge because he thought the girl was a guy who had been heckling him earlier. Apparently turning around to look and see who was there was out of the question.
Third, I'm not surprised that no one in the crowd decked him. It's pretty clear from the one guy that did get up that getting on the stage was not that quick and easy to do. Also, the punch was so unexpected and out of the blue, you have the "startle" moment when people are registering what just happened and try to figure out how to respond. Usually, the kinds of things that people are talking about, you can see trouble coming. You're in a bar with some ugly drunks, a skeevy character comes up to you, whatever - you're braced for trouble and ready to go at it if someone starts something. This wasn't like that. Sheer surprise, plus probably a fair dose of pharamaceuticals in the crowd, and no one knows what to do or what just happened. I once had a guy try to pick my pocket as I was walking down the street. Literally looked down and his hand was in my pocket, going for my wallet. I whipped around and stared at the guy, my brain racing to process what was happening, and thinking, "I should deck him." But before the signal reached my body to act, he ran off. Afroman kept playing after hitting the girl, but pretty quick the house lights came up and the cops arrived.
Finally, I'm a peaceful guy, I don't get into fights. But frankly, I think there is a place for decking a guy who crosses the line like this. I don't believe in a Big Brother state where the only acceptable response to someone doing wrong is to call the authorities. People need to know that there are more immediate, visceral consequences that are going to happen if they don't treat people right. Decking the guy may not make the world a better place, but a world where you can do what you please and be confident that no one will deck you, no matter how outrageous your action, is definitely a worse place.