I don’t think it necessarily excludes sex workers, it’s just one of those terms that means more than the literal words. For example, just because it’s not safe for work, doesn’t mean it is then safe for all other situations, like a dinner with extended family.

If you wanted to redo the term to be more literally accurate, I suppose you could say “About or Depicts a Subject that you would rather not have to explain or openly reveal to someone whose beliefs or relationship with you are not casual enough to ensure that, without a doubt, their comfort with you will remain the same after being exposed to your viewing of said content, either in a professional or publicly social setting”

I am honestly not sure how to make that any shorter while encompassing all of what I feel NSFW has truly come to represent for society. It’s similar, though not identical, to other words that may have originally meant one thing, but have come to mean another through the years.

You’re right, it’s a very broad term with a few weird gaps. Perhaps society will start defining some new terms, tags, descriptors or whatever to add that nuance. Good luck with your endeavors!