I wonder whether a less evil version of what Google tried to push would be a better solution to this.

That is, a user might flag themselves - or let their browser suggest something then accept it, but this is all local - as "30-40y old, american, male, passing interest in programming, big into archery and horseback riding", from a big list of possible interests basically. And then ad companies put ads into categories and that's how they get selected.

Also they willingly give it to the cops so they can harass you