Are you sure the City actually shut it down? Did you call 311 to ask?
The sign looks like it has been out somewhere for a long time. Are you sure whoever wrote the sign that is next to it didn't find it somewhere else like The Fly, and use it as an opportunity to make what they think is a really clever political point? I mean, I live right by City Park and it has been open the entire time. The small playgrounds here and there and the facilities are closed, but the park itself if open.