As explained on Reddit, several app developers like Simple and Swipe have received letters from Facebook attorneys forcing them to remove their apps from the Play Store. This has been discussed on Reddit, although the complete text of the letter seems to have been removed as well.Although I can expect replies like 'do not use Facebook' I still think this is a sad decision.
https://www.reddit.com/r/androidapps/comments/mkruz4/what_happened_to_facebook_wrappers_swipe_and/