This allied race is tied to a Dungeon , Vulpera were not . Alliance got the same path except for us Horde we had to make damn sure we did the whole mechagnome questline to unlock . Yes it could be intro quest involved however my 120 Pally alliance did the intro quest and still hasn’t gotten to unlock Mechagnomes because of the last quest to Kill King Mech. So this is simply a bug or blizzard just couldn’t have a patch that was complete.