No it's really not too simplistic. The only case where Facebook's censorship is a positive is if the following 2 statements are both true:

- FB's moderators posses better judgment than me as to what is and isn't true

- FB's moderators will always act in the best interest of the users and not the company when they come into conflict

I would say that the first point is very unlikely to be true, and the second is certain not to be true. I'm not sure how a lie can be harmful if it is know to be a lie.

I mostly agree with your point here. But a lie can be very harmful, even if it is known to be a lie, if enough people either don't know it's a lie, or don't care. See "Blood libel" for perhaps the most extreme example.