According to BoXXoB someone probably reported them for breaking from rules (incentivized posting which they encouraged back then) and i think from the look of things the responsible decided to lock the threads recently.
So far no word about the campaign stopping.
Now, you also said Alex closed the threads... he did not. As you would know if you had read my previous reply. That matter is completely unrelated to this entire fiasco.
We had an old rule in our signature campaign thread about posting on bitdice ann but that isn't enforced anymore. I believe someone reported the signature campaign post and now due to that, the threads are locked.