The industry is full of tiny little battering rams like subliminal advertising. Each attempt yields success or failure, rinse and repeat. The refinement at this point is unfathomable.
Manipulating people for money is ethically suspect. And the whole industry is an arms race: people spend money on advertising mainly because their competitors do.
If we banned all advertising tomorrow, consumers would still get about the same outcomes, especially now that the Internet makes it easy to find products and product information. Well, the same outcomes except they'd have circa an extra $1k/year in their pockets, and would spend a lot less time watching ads.
And if there's anything which recent history has shown conclusively beyond doubt, it's that people can be relied upon to give each other reliable and accurate information about people and products. Especially online.
That's surely what would happen if we banned advertising. One can already get plenty of great product information without advertising, and from the same kinds of sources you link.
What if you're advertising the historical equivalent of a vacuum cleaner over a brush? A dishwasher over washing up liquid, a car over a carriage, a savings fund that invests ethically over one that doesn't, a cheaper, faster municipal broadband over a monopolistic inferior broadband, the examples are innumerable. A progressive political party over a corrupt incumbent?
I agree in general that advertising should be curtailed from the present level, but I don't agree that it's fundamentally unethical.
If you've got to rely on word of mouth, even with the internet, it will take a lot longer for good, useful products/ideas to spread.
If advertising were vital for learning about new products, nobody would use open source software. Nobody would use Hacker News for that matter. They do, which should tell you there's something wrong with your theory.
Hacker News is literally advertising / lead gen for YCombinator.
Apologies for yet again picking a nit, but PR doesn't involve paid placement of a message. Neither does lobbying, media relations, inbound marketing (Hacker News), messaging, positioning, or getting an intern to stand with a sandwich board through the street. You could run a coach and horses through that definition of advertising.
That line runs between "let's think about this as an interesting thought experiment" and "let's do this!" - People can and are manipulated even when they know they are being advertised. That has been shown time and time again. Advertising is psychological manipulation with another name.
We can't abandon and block ads completely. If we did that, we wouldn't even get to be aware of products which might really make our lives better. How do we figure out the healthy balance out? I would argue that the current laws around advertising are pretty decent but they could be made better and adapted for social media platforms.