Resisting the ideology that only people with money can alter the city environment.

When you see an impressive sculpture or skyscraper you know a lot of resources were spent, you know the rich people here are rich. When you see an area with lots of graffiti, there may be many good or bad things about it, but you know the citizens are free.

I would hope graffitiers have respect to only draw on the mundane parts of the city, not on cool sculptures. And in my experience, that is true. Also they should not obscure windows or information signs.