Nikhil Sonnad, in Everything bad about Facebook is bad for the same reason:
…the imperative to “connect people” lacks the one ingredient essential for being a good citizen: Treating individual human beings as sacrosanct. To Facebook, the world is not made up of individuals, but of connections between them. The billions of Facebook accounts belong not to “people” but to “users,” collections of data points connected to other collections of data points on a vast Social Network, to be targeted and monetized by computer programs.
There are certain things you do not in good conscience do to humans. To data, you can do whatever you like.