This could be easily solved if moderation records were made public for public posts. Keeping the process opaque will never quell doubt about its impartiality. I know if I saw a record of what post was banned, which policy it violated, any appeals process records, and a list of previously banned posts by that user, I would be able to feel confident that the system was being managed well, and a strong defense for FB and its private judiciary to demonstrate its application of company policies.