Some of the more level-headed comments in this debate state the obvious... Disc golf isn't appropriate in some urban parks. Over the past two decades, the San Francisco Disc Golf Club has repeatedly tried to install a course in McLaren Park. Every time they presented their plan to the community, the community overwhelmingly rejected it. All city supervisors that represent the park oppose the idea. Most current Park Commissioners oppose it. Community groups throughout the area reject it too. In fact, outside the immediate disc golf community, it's hard to find anyone who supports the idea of installing a course in McLaren.
Maybe it's time that the SFDGC take a hint an give up on their McLaren plan. If they formally withdraw their effort to build a course there, I bet they'll stop hearing from Ken or the rest of Save McLaren Park. They can then focus their energy on beautification efforts at the GGP course, and possibly set their sites on other open space in the Bay Area... somewhere that not so highly valued by the community surrounding it.
It's obvious to all of us that disc golf continues to grow in popularity, but history will prove how environmentally destructive it is. Many disc golf courses are slowly evolving from lush landscapes to much more barren spaces, where grass is replaced with mulch and trees have to be protected by fences. The change is slow, making some people think the damage in minimal or forgivable. But over time even the strongest trees will succumb to the constant assault to it's protective outer layers.