A spokesperson confirmed this to VentureBeat via email. They said that most people who use Facebook Messenger already log in using Facebook anyway. According to the statement, the company want to “simplify the process”. Existing users who already use Messenger without a Facebook account should be unaffected.

That said, VentureBeat reports that some users without Facebook accounts had issues with the transition. Possibly due to a bug, users report an error message stating that their account has been restricted. It’s unclear at this point what drove Facebook to come to this decision. It may have something to do with the company wanting to allow all of its messaging apps to connect to one another. After all, WhatsApp is already a messaging app that only requires a phone number to work. All that said, the merger may not even come to pass, as it may face resistance from the US Federal Trade Commission (FTC). (Source: VentureBeat)  

Facebook Messenger Needs A Facebook Account For New Signups Once Again - 71