My app Vampires was rejected for using Facebook login. I have a very similar app called Pirates which was approved. (https://itunes.apple.com/us/app/pirates/id312324127?mt=8)
The app review response:
November 23, 2015 at 9:48 AMFrom Apple
17.2 - Apps that require users to share personal information, such as email address and date of birth, in order to function will be rejected
Thank you for your response. We are not able provide feedback on app concepts or features but we recommend evaluating your suggestions against the App Store Review Guidelines, as well as the iOS Developer Program License Agreement (PLA), and the iOS Human Interface Guidelines.
Additionally, if you are considering implementing any of the following functionality, we recommend reviewing all associated reference material and other resources available in the iOS Dev Center for any additional requirements.
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