There are only few ways to monetize a business model. While some people object to any ad supported business, others only to data driven ad business, and others care about specific pragmatic day to day consequences on people's privacy. It seems that last category where Facebook is more likely to complicate people's lives.

Also, perhaps, pagerank is viewed as an innovation founded on real technical insight, as opposed to Facebook, which basically recreated MySpace (etc.), initially resegementing the market by serving privileged Ivy kids rather than lower status music fans. That's not the sort of story that people valorize here.