The account in that screenshot appears to be on a self-hosted instance. That is one of the recurring sources of moderation troubles: some new actor can create a pop-up harassment node. Since there’s no instance-level moderation, every •other• instance has to block the account •individually•, which takes time.
(Of course, self-hosted instances are also more vulnerable to attacks of various kinds, and are paying for traffic out of pocket if there’s a DDoS, so…real tradeoff for the trolls there.)