They did this kind of stuff in 2000 too,
when "protesters" were brought in during the Florida recount. The goal then was to disrupt democratic processes and that goal is little changed.
Beyond that, their intent is clear. They want to create the impression that disagreement with the Obama Administration is not only everywhere, but is of the same intensity everywhere. Your average viewer sees these protests and thinks, "My god, they're protesting in New York. But New York's liberal!"
It also appeals to the media. August is a slow news month and these confrontations, however fabricated, provide a nice storyline.