Sometimes graffiti - however objectionable and anti-social it is in principle - can be very thought provoking. There's a wonderful slogan daubed on a fence alongside the M40 coming into London that says, 'Why do I do this every day?'
The Sun have headlined this TOP TORY: GRAFFITI IS SO GREAT. Other papers have done him over too. What a pity it is that it is now virtually impossible for a politician to give their true views on something without the nation's media descending on them like a ton of bricks. All they achieve is to put other politicians off saying anything remotely interesting at all.
FWIW I agree with Jeremy. Although I strongly object to most graffiti - sometimes it is highly artistic and often very amusing. However, if it is your building thatr has been sprayed on, i's clear you won't find it amusing. At all.