@mwlucas I just tried to use blacklistd to protect my host's sshd and it seems I can't get this to work either. I added UseBlacklist yes to the sshd_config and restarted it. But blacklistd doesnt receive any events according to blacklistctl.
Either I am missing something, or sshd's UseBlacklist is broken on FreeBSD 12 (very unlikely to be honest).