Most of that inference actually comes from the pervasive "like" buttons -- essentially all of the websites you use are happily and freely giving the information

Most of that inference actually comes from the pervasive "like" buttons -- essentially all of the websites you use are happily and freely giving the information about you to facebook - who gladly correlate it across sites and with your shadow profiles. Your friends who uploaded their addressbooks and phonebooks to Facebook and WhatsApp are obviously helping to associate that data with a real identity, and by tagging you in pictures make it even more complete. But the vast majority of info Facebook has on you that YOU did not provide directly actually comes from the embedded Facebook bugs ("like buttons") all over the internet. And it's not surprising that the media doesn't mention it -- they rely on those bugs to get traffic, so they can't complain about it without taking it off, and they can't take it off without losing traffic.