I have no idea if Bez is being serious or not. But then I guess if he can find beauty and interest in surroundings that most of us would deem ugly, then it's no bad thing...
Deadly serious. Without graffiti the plaque would just be a relic. Without the layers of posters the shop front would just be a plain surface.
We all ride bikes, right? We all dig scars, right? Scars tell stories. At the other end of things you have glossy magazines with airbrushed, Photoshopped skin. What story does that tell? Nothing, it just hides things.
Bez's war memorial taggers would be a couple of drunk morons kicking a metal bin around outside your bedroom window at 4 in the morning.
No, that's an engraved Roman plaque on an amphitheatre and most if not all of the graffiti are not tags but people writing their sweethearts' names - note "ti amo" in the middle. So in this case they're not drunk morons, they're average Italian teenagers drunk on love and escaping the crowded family house for some stolen moments. "Ti amo" seems to be the most common graffito in that area - in fact apart from a few gang stencils as you move into Naples it's all astoundingly joyous stuff.

Isn't that great to have in your streets?
And the fly posters? That'll be the local hot-shot priests.

All of which of course you'd miss completely if you take the blinkered view that anything that doesn't resemble a Turner painting can't be good and anyone who scrawls or airbrushes in public is disillusioned, or malevolent, or a drunken yob. But for good or bad it reflects what's going on around you. It fascinates me - it's real stuff. I end up wandering off round back streets whenever I visit anywhere, and don't forget of course that unlike most tidy and sanitised art galleries, it's free
Where's the harm in the whole urban environment being a living work of art? It is after all a work of science, of engineering, of geography and politics - why can't it be a work of art as well?