"Taking Back the Parks" was a well-written but depressing review. But what's new? A small minority using tactics the majority are loath to employ has usurped public property and put people in fear. Nicole Yorkin places the fault with Proposition 13. Hooliganism similar to that in Los Angeles exists in New York, Chicago, Detroit, Washington and many places where there is no Proposition 13.
Possibly if the small number of destroyers in a community could be identified, the large number of producers would take courage. The ratio is probably much less than 1 in 100. With the positive approach that seems doable.