I don't see where he is arguing about or denying the cost of big data, all he says is "five years ago hardly anyone realized that they had data." Do you disagree with this claim that most people were not very worried about their data before tech companies started finding ways to mine it for profit? In other words, the problem of tech companies assembling digital profiles of customers is a direct consequence of our use of their extremely popular services. Even today, people say they want companies to collect less data, but most are not willing to pay for more privacy. If your concern is election manipulation, this seems an inevitable side effect of any mass communication technology: television before the internet, radio before television, newspapers before radio. But again, the author does not deny these negative side effects, he merely claims that the benefits are so great relative to the costs that the unrelentingly negative commentary about tech companies is unreasonable.