I'm not familiar with the finer nuances of the McCormack case but I do wonder what the main difference is between his and Adam Back's case is. They both reside in the same jurisdiction and they both referred to Wright as a fraud. Do you have any insider information you can share about how Back got his suit dismissed so quickly?
AFAIK the primary difference is that when Wright acted against Adam, Adam didn't make it public and give wright free publicity (I'm not faulting McCormack here-- he needed public support), and Adam appeared to be in a position to outspend Wright. It's also the case that what Adam said made for a simpler and easily defended case, e.g. more squarely centred on the unambiguous fact that all of wright's "evidence" was fraudulent. Otherwise, I think it was just a question of having multiple ongoing cases being an extremely poor legal strategy. It may also be that wright realized that having to provide discovery to adam might end up exposing other actions by wright that he didn't want exposed.