Well they are talking about that because the necessary tools to block at a community level are not their at the moment.

They are either proposed to be added at a future date or being worked on for future iterations of Lemmy.

That or if a group of devs not tied to actual Lemmy development, decide to fork it and develop such a feature in their forked version of Lemmy, it will be a while before such a game changing feature like that makes it into the upstream.