Graffiti - art or vandalism?

"Graffiti, illegally placed in public space, is treated by some as an act of vandalism, by others as an art form." It's a Wikipedia quote. But I don't mean the definition or the history. What puzzles me is, why those who paint want their anonymous painting efforts became well known and public? Can this action be compared to the activity of a troublesome neighbour, forcing everyone to listen to his favourite music? A neighbour who implies that it is only the adversity that makes him a listener and not , for example, a disco polo star? Both graffiti artists and people deafening their neighbours want to become known, but the latter are noncreative. Simply turn the knob, move the slider to the right or use the remote control. In turn, those who paint on walls, fences and wherever possible have a certain idea. To realize it, they have to plan it, buy materials, choose the time and place. Sometimes it is more spontaneous, expressing their disapproval ...