Sure they can, they can ban the user from the entire instance or from the community. To all users of sh.itjust.works for example the content will still appear, but it won’t show on beehaw anymore.
Here’s the PR that implemented this: https://github.com/LemmyNet/lemmy/issues/1298
Wtf just do your calls in the stairway awkwardly smiling at passing coworkers like the rest of us