Banksy is a grafitti artist that is popular for his meaningful pictures. His art displays contradictions in political events and things such as peace. His pictures point out injustice and I agree with the points presented. It seems like everyone has a hidden agenda and thats what the picture of the dove and crosshairs is about.
Graffitti is a form of art however most of the time people dont do it to their own property which is were the conflict arises. I think there are two types of grafitti the first is a show of artistic views while the other is somebody bored with a spray can and deciding to just write a name.
Many people see tagging a building is not art it is destruction of property that has to be removed by workers, so in the end it may look cool but its resulting in someone having to take care of it. Writers and artists use pen names because if their work raises a fuss then they wont be in the hot seat.
Displaying your art in public is fine but if it costs other people money to clean up a building you tagged then thats irresponsible art. The bottom line is grafitti is art building tagging is not.