Our world is principally defined by separation. A store exists for commodities to be exchanged, not for mid-afternoon parties with a community of acquaintances. A high school exists for indoctrination, not for communicating freely with friends. A wall exists to support a structure, not to be painted on.
For some, graffiti is an attempt to break the separation between an impersonal urban landscape and the vibrance of life. It is a very literal assertion of the value of creativity over the sanctity of property, a visual declaration of the will to live. Politicians, from positions of unchecked power, simplistically assert that graffiti is "wrong". They attempt to coerce their constituency into assimilating their morality, as if "right" and "wrong" really are objective terms. For writers, the world isn't so *black and white*. Why, asks the writer, can't the dead walls of our city become the canvases of our aspirations?
Of course, there are very real reasons why youthful creativity is so brutally repressed. It forces a reconsideration of the real nature of property relations in regards to the lives of actual people, in short, it calls everything into question.