You realize that's not true? If you choose to enable the "Contact Sync" (the only time when they are sent your device's contacts), this page is shown: http://static.guim.co.uk/sys-images/Technology/Pix/pictures/... Unlike the Path scandal earlier this year, Facebook has done a consistently reasonable job warning people about what they are doing (as well as having the feature off-by-default and, even if you want to use it, somewhat difficult to access).