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.
To the contrary: defederation from instances in situations like this is very much in the spirit of the the fediverse. Not attaching NSFW tags to NSFW content is a major moderation fail by lemmynsfw, and restricting content from badly-moderated instances until they get things cleaned up is something that frequently happens.
