A DJ forces everyone to look at each other, for a lack of interest in anything a DJ could possibly be doing.* People circulate even if practically, the music neither begins nor ends, and people commute at any time, during the music. People move freely.
A band starts and ends encouraging a continuous waiting: waiting for the band to finish, waiting for the band to start, smoking, pissing, creating anchors cast of bodies. It is an "event" which implies a goal however subtextual or subconscious: "to see the band." It provides a need and reason to go out and simultaneously an excuse to not participate. The responsibility for the fun lies with the band. It is anti-social.
A DJ gives no excuse. People are forced to face each other and they confront themselves, the social, people, as the thing, not to be witnessed but as experience, as activity. By lack of outside reason for "going out" the activity is yourself - the responsibility for fun is on you. People who need people.
Unless it's a real shitty DJ who just can't for the life of him play a single good song.
*Even a superstar DJ gives little reason to watch. In all the videos of Richard D James performing, he has only once "expressed" anything, appearing rather aloof, almost apathetic. The laser light show always seeming a sort of raised eyebrow asking, "Did you really come here to watch psychedelic videos?"
