The folk revival was pretty closely tied to "left" political movements, from the labor movement to civil rights, and the Vietnam war. A lot of times,union halls, churches and coffeehouses that were used for organizing were also used for concerts. One of the reasons that folk music never became a lasting part of popular music probably had to do with the strong political orientation of many of the performers.

The point being that, politically, you knew what you were going to get when you paid for your ticket. Michelle Shocked, however, has cultivated a "gay" audience and basically, told them off. It was obviously deliberate and planned.