Luckily there is something in between "ugly advertisements" and "no advertisements at all"
As for making the city ugly, I grew up there and I’m the first to say it’s an acquired taste. You get used to the grit, to the harshness and the layers of architectural history. Visiting the city centre is always some sort of a discovery.
You speak of the grit - said grit could be improved with government efforts funded by... advertisements in part.
I suppose this lack of nuanced thinking is why the war on drugs is still a thing. There are many bad things that you can try to unliterally ban. There are tradeoffs.
> In September 2006, the mayor of São Paulo passed the so-called “Clean City Law" that outlawed the use of all outdoor advertisements, including on billboards, transit, and in front of stores. Within a year, 15,000 billboards were taken down and store signs had to be shrunk so as not to violate the new law. Outdoor video screens and ads on buses were stripped. Even pamphleteering in public spaces has been made illegal. Nearly $8 million in fines were issued to cleanse São Paulo of the blight on its landscape. Seven years on, the world's fourth-largest metropolis and South America’s most important city remains free of visual clutter and eye sore that plagues the majority of cities around the world.
You're right though. Uninformed people who don't read the article are annoying. I'm not even for ads. It's simply that there's a way to do outdoor ads that doesn't ruin the city.