Board Thread:Support Requests - Getting Technical/@comment-24383490-20150915060906/@comment-5558012-20150915134327

Quick questions to ponder, if you are set in the idea of protecting all pages from new users, what are actual new users going to do? Is a new user going to stick around if all pages are blocked from editing by you?

Your problem sounds like something you should inform the VSTF with so they can help. Mass protecting pages isn't allowed on Wikia, I don't think blocking all new users is any different.