Who defines public space?

Although I am not too knowledgeable on Margaret Crawford’s work, I really appreciate her notion of “everyday urbanism”; celebrating everyday life, seeing over the “banality” and recognizing potential and character.
With that said, I really liked her article “ Contesting the public real. In my opinion, public space has become, more and more, a difficult notion to define. With the integration of Landscape, Urban Design and Architecture, the exterior filtering in and the interior spreading; the celebration of infrastructure (originally seen as the “private” and hidden part of an intervention); etc., these boundaries of public and private have blurred even more. It is no longer black and white, but an array of “grays” (semipublic, semiprivate, etc). It depends on perception, which itself depends on the culture (a half opened door can be an invitation in one culture while meaning the opposite in other).
Nevertheless, in this article, Prof. Crawford focuses on another notion of public. It is a “public” steaming from public action, or more specifically, public reaction. It consists on people (usually minority groups) coming together, protesting on their right of citizenship, and therefore bringing a once private issue put on the table for everyone to see and be aware of. In this case, it is not that much about public space but the exertion of public rights and the appropriation of space to do so. Designed space no longer takes the stand, but it is the “everyday” which gets the spotlight (sidewalks, streets, etc). This brings me back to the first readings we explored, the Harvard Design Magazine discussion; can public space really be designed? Is it defined by the users? Maybe it is both as architecture and design have the potential to created and invite these many public gestures…