Easy, it just means advertising doesnt cover everything. The fact that they know so much about you is valuable in itself and they can sell access to that data, for example... to cambridge analytica. Advertising is just one of the ways in which corporations exploit information to manipulate people’s behavior.
Please elaborate on how i've been misinformed in this respect. I've gotten downvoted a bit without much feedback. Also, since the distinction matters, I would like to point out that I claimed selling "access to" that data, not selling the data directly.
