If ads were merely about being informative, they would be boring. But ads want to manipulate, so they have to be flashy and appeal to your emotions.
They pollute your mental headspace, and have no place in a healthy society.
Let's ban billboards. And then let's follow that up with a general purpose ban on paid advertisement.
Advertising is how small and new companies can reach customers. It's how monopolies are broken. It's how progress reaches the masses.
Yes, it is willfully intended to change people's behavior. So are many of our posts on HN. That is an important purpose for communication!
As for all communication being a bit like advertising, a significant threshold has been crossed once you're paying to have your information elevated above that of your peers. If we didn't allow that, the noise floor would be lower, and it would be possible to achieve the benefits of advertising without the harms.
For instance, suppose I'm looking for a plumber... there are only maybe fifteen within a reasonable distance. There's no need for the plumbers to pay some third party for the privilege of being first in the list. I can limit my search criteria so that the results are narrow enough that I can consider each one, and they can instead spend that money on pipes or toilets or whatever.