The two top entries on lemmy.world sorted by hot as of a few minutes ago were a porn link on a porn community (nothing against porn per se, but I don't want to see it on the front page) and a bot post to some kind of bot link community. I see the "block user" button but I don't particularly care to see anything from those communities, so blocking the individual poster doesn't help much. I could actually visit the community in order to block it, but that sort of defeats the purpose of blocking. And I know of "Hide NSFW" but I'm not particularly anti-NSFW, I just don't want to see it unintentionally.
So it would be useful to have "block community" as an option along with "block user" in the little buttons underneath the post.
As a broader policy matter, I'd be cool with blocking NSFW from the front page altogether (it would still be available within communities of course). But I understand such a decision would want discussion for and against.