They know they're not supposed to be on Facebook according to Borg directives and so they overcompensate with over the top "spiritual" Wall posts to assuage their guilt. They're like the JW lesbian couples who become "pioneer partners" thinking that Jehovah won't kill them for loving each other as long as they put in enough field service time.
Regarding JWs on social media: "It's sorta social. Demented and sad, but social."