Many cities here also have walls dedicated for graffiti and such to give street artists some space and bring some color. Some small infra-related buildings also have street art done on commission and they look great! But shitty tags and graffitis still exist and my impression has always been that the maker probably wasn't thinking about art or anything deeper for that matter...
Was the graffiti made with approval of the owner of the building? Does it fit general aesthetics of the city? Yes and yes - it's finally some colors. Otherwise it's a vandalism.
If it's a public building - it's vandalism, unless it was decided by all people living there.
> As an art person I really see truly good graffiti, yet I have to notice that heavily graffitied parts of my city are tourist magnets — so many people tend to like those "defaced" walls.
Yeah, way to make life hell for residents of the neighborhood.