The answer to your confusion is that un sophisticated remarketing (showing ads for searched or purchased items) has in nearly all cases a measurable improvement on ROI. Improvements to filter out useless ad views are much more complicated and expensive.
Advertisers actually don’t care about any individual case, but buy on aggregate results.
Oh I don't think anyone is confused about why this happens or why it's still worth it. The next step we need to take is to agree that it is unethical to steal many people's time for a little reward.
