Maybe I’m misunderstanding but I’m using Connect for Android and I just tap the options for the post and I can block the user, community, or instance. Lemmynsfw was the first one I blocked and I haven’t seen anything since.

Also, apropos of nothing else,when you block a user, you still get an option to see their comments (it’ll come up as this user was blocked) but then you click thru to see it.