There is a substantial amount of spam and NSFW posts on the All page coming through already. Most NSFW posts aren’t being tagged as such and are coming right through. I am not sure how this can be weathered but we need something in place fairly soon, I feel like we are days away from rivers of bad stuff, especially via some of the federated instances.
EDIT: I personally don’t care much about the NSFW aspect, more in the lines of what a newcomer will be seeing when they get to the main page. 99% of the newcomers don’t know / care about federation and have no idea how to turn that off. Liability for the server owner is also an element of consideration.
It’s not entirely intuitive since your profile only shows you what you’ve blocked and doesn’t give you the option to block things. You can navigate over to https://kbin.social/d/lemmynsfw.com and scroll all the way down to the bottom there will be a section with a header called Domain that shows the subscribed users, and two buttons, one for subscribe and one for block. This is how you block a domain. Repeat with links to other Domains that have content that aren’t properly flagging posts as NSFW.