Wouldn't surprise me. The people who work at Facebook drink the Kool aid to such a degree they believe anything they do is in service of the greater good.

On top of that they have had those "social maps" since at least 2008. With the amount of data they have and their capabilities now it would be trivial to accomplish something like this. Wouldn't be 100% perfect but doesn't need to be most people are not that discerning