Your assumption that content people might find--Facebook or elsewhere--that is more harmful to them than a censorship policy just handed down to them--is false. This is your chance to confront the people asking you to implement the policy with a couple of questions:
1. Given all the ways people get uncensored internet even under autocratic regimes where the penalties are brutal, what makes you think any censorship policy could work?
2. Which feasible projects are you willing to divert resources from in order to tilt at this windmill?
Don't let them answer 2. until they've got 1. well in hand.