The nsfw is just a tag people use to identify their posts as being not safe for work. You don't see it because UIs handle this tag specially. I have never seen it referred to as a 'blacklist'.

If I want to no longer see profanity, we could tell @SteemPeak developers that it would be good to have a profanity tag that users could put on their posts. This is the honors system and it's a good idea. The poster has to use the tag and you count on them. If they don't do it, then what?

Blacklists are by their nature not something members of the said list opt into. It's for the maintainers of the steem sites that opt in to the black lists. This is the UI level. Talk to the maintainers of the UIs to no longer subscribe to these lists or appeal to the list maintainers. As a third option you can support a competing Steem site. The users that support my web-site will be the whales of that site. Those that do can maintain the black lists or make sure blacklists are opt-in only.

Take a look at https://www.steemfiles.com. It uses steem for logging in and shows you a price ticker. I could add features like browsing articles and posting, and the investors will never see their posts hidden on steemfiles.com. I could setup an investment scheme where twenty people invest 100 SBD and they get a site on the Steem blockchain that ignores flags. Rewards are on the blockchain level though so there is nothing I can do about that.