This is usually the work of a rogue body of dumbasses. I've seen elders make stupid rules only to have the CO come along and yank the rug out from underneath them. But it is interesting how local bodies of elders come to create and enforce rules like that.
I happen to know a Bethel elder who is on Facebook. He doesn't post a lot, or of anything noteworthy, but he's on there and he uses it to stay connected with family and friends back home.
I wonder if an elder body would reconsider their decision if they personally knew elders and Bethelites who used the network similarly?