Why? Anyone could easily tailor their relays and follows for NSFW content.
Why would you use a Twitter interface to browse NSFW content? UI/UX can be so much better when you know the type of content coming at you.
On another note, I don't understand how all these really operators continue to run without any income, especially if you're uploading tons of media to these servers like Nostr.build
Some of them do have income, but it's about selling access to data. There are trillions of dollars to be made with the right (for a VC) business model. If you don't pay to sustain what you want, you become the product. That's true even here.