Earlier quoted context omitted.
i'm by a longshot no facebook fan but... are you sure the SDK can actually siphon out what songs you listen or your location from the app it's sandboxed in (which, BTW, is in its own sandbox from an iOS system POV, and also has its own set of permissions)?
Well the reason FB/Foursquare/Google etc add these to 3rd party apps is so they can get data. Example if you visit a website which has a Facebook like button, your browser fetches the js files/which maybe even makes an API call to let FB know your IP (and hence location). All this data is fed to the giant system that feeds you ads. Adding their SDK to other apps/sites (even if there is no user facing need) is a commo…
I doubt (and at least from my experience around SV, haven't seen) that FB/Google are paying apps to include their SDKs.