I couldn't make much sense of that post either, despite several attempts at reading and re-reading.
I don't share the detestation of grafitti of many on here.
Graffitii is often not likable, but there is much, much more in our cities which I find visually offensive, some of it: much more offensive and much more permanent than grafitti, and most of that is corporate grafitti (massive illuminated signs & logos), architecturally impoverished construction (bland concrete shopping malls, car parks, shop-front conversions) and painfull neglect of our natural envionment.
I find these to be more offensive than any grafitti. And I've yet to be persuaded that the concrete excrement in London's Stratford (anticipating 2 weeks of globally popular activity and a legacy of shopping) isn't a more permanent form of graffito.
In fact, I'll go as far, in response to the OP, as saying that if any visiting tourist who visits the UK on account of the Olympics and contemplates London's visual impact, then I'd hope that they obtain a realistic impression of the City from whatever they see. Lets not lie: If that is how London is, then let's not pretend that it's otherwise.
I detest deceit.