There is a big difference between mild NSFW and full on porno. Suppose there is a News story with photo/video but it's a little bit graphic or violent. Nobody is jacking off to that. Maybe shouldn't view it at work, but in the library is fine.
Maybe it's a funny meme pic but there's a nip slip situation going on. No biggy; it should probably be tagged NSFW. Probably don't want it showing up at actual work. But I want to enable this kind of content away from work without a bunch of actual porn showing up in my feed.
There should be a porn tag. It's not the same as NSFW.
EDIT: The two main devs have done some amazing work here, but as I understand it they are totally booked for the foreseeable future. My rust chops aren't quite up to snuff (yet) and my frontend chops are non-existent, so it might be a quite while before I'm up to speed enough to make a meaningful contribution. In the meantime just thought I'd point out the issue.
The biggest issue I have with defederating is that you basically exclude every member of that instance from discussion on other instances even when they keep their nsfw post completely within their own instance.
If I'm on Instance A that defederated Instance B because it's NSFW friendly, then I also can't see comments from members of Instance B in completely unrelated comunities on other Instances.