Well in the case of NSFW I disagree. Simply because just imagine you browsing steemit in public or around your boss if at work or not and suddenly a picture of a naked person poping up. However you explain it, it will impact the opinion people have on you and it would be sad if you had to stop browsing steemit in public.
Decentralized or not a group of people still gives themselves rules which everyone should abide by. The only difference is if the rules are made by more or less consensus or given by a certain group of people.