No successful company deliberately mocks their player-base, at least not openly
I think Blizzard has tried to accommodate the desire for Alliance High Elves as best they could by first introducing the Silver Covenant in Wrath and making them the counter part of the Horde Blood Elves in a lot of story lines. Given the continued popularity/desire for Alliance High Elves they now used Allied/Secondary races to give Alliance players the model in the only way Blizzard feels they can, by making them look distinctly different from Blood Elves and giving Horde players the Nightborne in return.
It may take Alliance High Elf fans some time to realize it but I think that despite their crappy introduction Void Elves are more interesting for the story with regards to fighting Old Gods or Void Lords. We'll have to see what happens to the Silver Covenant in the future but I wouldn't be surprised if they show up again in 9.0.