What about the fact that ads are the only reason garbage such as clickbait and misinformation exists? A lot of that garbage wouldn't exist if its only revenue stream wasn't there.

What about the countless scams or dubious products advertised in Facebook ads while you look the other way because they're still making money for company? If you have the power to broadcast content to a major part of the world's population, this should also involve some responsibility and strict controls on the content, aka thorough human reviews. I don't care if it makes the prices of the ads go up; legitimate brands will still be able to afford it, and the market will become a better place for everyone (plus maybe with less crap in the ads people will actually like them a bit more).

Finally, if you want to do ads, why not just ask the users what products they're interested in, categories they belong to, etc and use that for targeting instead of stalking their every move to try and infer this information?

I suggest you read this regarding the negative impacts of advertising on society: http://jacek.zlydach.pl/blog/2019-07-31-ads-as-cancer.html