I don't really see where the victory goes to the hackers in this case.
Of course there are always two sides of a story but at the end only the result counts. And in this special case the winners are the players, server admins and of course the AC itself.
Because every AC have its own ban system and ban period for different violations there are always problems in keeping the shared bans synchronized. So many players got unbanned by one AC but still being banned on the other AC because the ban list isn't sync'd. Same goes for Bug-Ban-removals.
Also banned players now know exactly where to go to when getting kicked, since every AC have its own kick message (including the AC url).
Server admins that choose to stream to all ACs will have all bans and takes only 1-5 minutes (depends on the register steps of each AC). Since the most ACs using the live ban system there is no need to upload any ban list. Means less work for the admin at the end.
If a AC decide not to share its bans, then this is their right and also gives them the full control over their bans, without the need to inform other ACs about bulk ban-removals. Also they keep their own justification.
What would be the need of streaming to different ACs if you get all bans from a single AC. You wouldn't even think about to stream to any other AC.
In short, I understand the decision of PBBANS and respect it.