Seems like the solution here is for Facebook to consider Quest activity (playing games, active session on the device etc.) as legit Facebook activity.

Surely this is a glitch, probably happening in small numbers, that'll get sorted soon enough?

Why on Earth would they want to ban active users of their VR headset? Every active VR user, even if they don't use the Facebook site, is surely a precious asset. If Facebook continues to move into VR and AR, then surely many of its future users may only be interacting with its services exclusively in those mediums.