People call it 'advertising'. It's someone's or some company's tag and their design, and this graffiti is all over the place in the city (and some in the country too), and nobody likes it. I've never seen advertising that I would keep there if I had a choice, and it fills cities - just imagine a city without it.
Why should the wealthy, already with enormously loud voices, get to 'graffiti' the city and kids trying to express themselves and have any voice at all get criticized and arrested? I know the literal answer is property rights. In this case, that system excludes 99.x% from any voice or public expression; the real question is about justice and public good. (It's a philosophical question to explore the issues, not a policy proposal.)