the only mass solution i found to this was that i installed pgadmin, logged into the db, and manually removed all the bot accounts from local_user. you should also remove them from the person table as well (you can easily find them if you do SELECT * FROM person WHERE local = true ORDER BY published DESC in the query tool), that way they don’t show up in your instance stats, but removing them from local_user would be enough to stop them from logging in.