Thread:Applemasterexpert-fduser/@comment-33774728-20190226162406/@comment-34804319-20190227161430

That blog is nearly two years old, stating the creation of a new group. Since the group has now been in full swing since then, new members are chosen by staff, as told to me by several conversations with existing GDMs

In short, while it was possible to apply when the group was being created, now that there are many existing members, new users are only chosen if staff feels their contributions are worthy of the promotion.