> „Public spaces“

Usually buildings have private property owners. They agree to putting a bill board on their wall or they don’t. Graffiti sprayers usually don’t ask for permission — and that’s where the difference comes from.

In Europe you don’t usually have huge bill board on buildings. Rather you have lots of advertising columns on the side walks (here in Berlin we call them „Litfaßsäule“ named after the local inventor Paul Litfaß in 1854). You could argue they being a nuisance for sure but before the internet and even before radio and tv it was an important place of public communication. Actually they were an improvement because prior to advertising columns advertisers were wildly plastering anything with posters.