The original blue comment on locking servers was that transfers weren’t working sufficiently to end queues and more people needed to move, so they took the “very heavy-handed” approach of locking the largest 4 servers (Bene/Grob/Faer/Skyfury). Sulfuras was reaching ‘close to full’ so they decided to end free transfers there. But apparently they went so far overboard with Sulfuras that not only did they end free transfers on 9/9, they fully locked the server and to avoid the same situation on Eranikus it was functionally locked as well. I say ‘apparently’ because there has been no further blue update other than a note about a bug.
So due to their own error or incompetence, Sulfuras now has to be locked. However, Sulfuras doesn’t have free transfers anywhere else to reduce the population which was the planned solution on the other locked realms, i.e. the server became overpopulated because of their mistake and now they are doing nothing to address that overpopulation.
If you did what Blizz wanted and transferred to Sulfuras reduce the queue problem, if any of your friends didn’t make it in time or want to join fresh that’s too bad, pay up and transfer again (if you’re even able with the time limit on transfers). If you were already on Sulfuras and have friends that want to come back for wrath that’s too bad, pay up and go to some other server. Seems like there’s a common denominator here.