Group creation is not a secret. BlahTherapy has been under attack from a spam organization for some months, and they were inflating group numbers by the thousands with their spam groups. As a result, BlahTherapy group creation is disabled for the foreseeable future.
I believe if I am not mistaken that you are unable to actually create new groups right now. Although I am sure there are others who might know more, but I gave it a look myself and that is what I have concluded for now.