Using vandalism to communicate clearly vs. mere acting-out in SF's Mission

This is from an article in this week's 'New York Times;'

http://www.nytimes.com/2012/06/05/us/san-francisco-tech-boom-brings-jobs-and-worries.html?src=recg

Refering to the current phase of San Francisco gentrification, and the corresponding obvious total lack of resistance, the article states:

"...Back then, antigentrification posters appeared in the Mission urging people to vandalize luxury cars parked in the area.

It is perhaps a measure of how neighborhoods have been gentrified in the intervening years that few marks of protests have appeared this time."

Hey, why didn't the 'Times' mention that all-important nocturnal spasm of this past May 1st? Was it done by people who are incapable of speech? One month later and nobody even remembers that it happened -- but those posters from thirteen and fourteen years ago are still being used as a point of reference here.