I'm not saying they're completely equivalent but as a result of this whole tracking there are rather complete profiles about millions of people in some companies' DB, including hyper sensitive data such as sexual and political orientation which is just one The Purge scenario away from being abused on a massive scale. But even at a smaller scale, this data can be extremely (incl physically) harmful to individuals when leaked or when it falls into the wrong hands (Eg gay person in Uganda. EDIT: or a completely normal person in a future McCarthy-style witch hunt).

You're right. I'm sure finding a search history looking for domestic abuse shelters couldn't possibly cause physical harm. I'm sure that location data showing regular meetings with known AA members couldn't possibly cause harm to a career. I'm sure that somebody's adult website preference couldn't possibly reveal somebody's sexuality, and that nobody would have relationships hurt by having them revealed.

And of course, these databases couldn't possibly leak. Otherwise, we might conclude that these are databases that can hurt people, and should not exist.

What of the data is leaked? What if an inappropriate targeted ad is displayed when someone looks at my screen?