It isn’t arbitrary, either. You’re having a tantrum because you don’t want something added to the game and trying to justify your own selfish need to say “no, don’t put that there in MY GAME”.
Vulpera have more connection to the Horde at the moment than Void Elves do to the Alliance.
Vulpera are fine. We help them in quests, they help us, they have background and support. They have a reason to be an Allied Race
Void Elves remain my least liked race in the game and I wish I could remove them all and have Broken instead given their rep was for the Broken and all.
Clearly you didn’t find out about the most recent leak from the 8.2 datamining.
(EDIT) Honestly the delay might in fact be due to the fact Goblins and Vulpera share the same rig and Goblins are being redone. So perhaps 8.2.5 for that. I mean I am sure they want to keep Goblin players happy.