Why is it a problem if the user searches/shops for diapers, and then advertisers show diaper ads? The person is interested in diapers after all, and you don't just buy diapers once.
1. If I search for diapers, and get ads for diapers, the usual pattern is to show the ads above the real search results, which tricks people into buying more expensive and/or lower quality products (after all, why else would the company need to pay to show up at the top of the search results?).
2. If I search for diapers on one site and get shown ads on a different site, then it follows that companies are trading information about me behind my back, which is not okay from a privacy perspective.
Because it's none of their business what websites I'm looking at, especially completely unrelated websites. Remove the re-targeting and tracking then they don't need to know who's looking at the page.
So you admit to being an extremist then. You probably find problems with a great deal of the modern world as well.
You can't buy things online with cash. Your opinion on what people do online is therefore, colored significantly and is definitely out of touch with most people's experiences.
Declaring anyone who disagrees with you (and acts on those ideas) as an extremist is a neat trick, but the only thing it actually gives you is an ad hominem.
1. If I search for diapers, and get ads for diapers, the usual pattern is to show the ads above the real search results, which tricks people into buying more expensive and/or lower quality products (after all, why else would the company need to pay to show up at the top of the search results?).
2. If I search for diapers on one site and get shown ads on a different site, then it follows that companies are trading information about me behind my back, which is not okay from a privacy perspective.