https://forums.oculusvr.com/community/discussion/92257/required-facebook-for-authentication
>New accounts and new devices will require a FB account starting in October. If you have an already-existing Oculus account and an already-owned device, you will not be required to link or merge a Facebook account. As of October, you will have to permanently merge (rather than link) a FB account to access social features.
>After 2023 you will still be able to use your old device and old content without a FB account, provided that the game devs continue to support that content without requiring FB accounts.

So, apparently if this is to be believed then people who already own an Oculus headset and don't want to merge with a FB account can still access all their stuff in 2023 and beyond but will have issues with software that'll require FB/social media-implementation.
I guess if you only deal with Oculus- and Facebook-unrelated software then this should be a non-issue as for now.