I don't mean to shock you but as someone who worked on a game that interacted with facebook data - everyone in the world is harvesting some information from facebook when they're making calls to their API. Sometimes it's as "innocent" as spamming your friends with requests to play (or enabling the user to do that for in-game rewards!) and sometimes it's cambridge analytica. No application in the world just wants to altruistically be helpful by having a facebook integration - I can't even imagine what that'd look like it'd probably, honestly, be just not having a facebook integration at all.