I can’t speak for everyone but as a lore nerd? It upsets me because of the lore associated with the alliance and the elves.
Gameplay wise? I feel like they’re being cheap, cutting corners and just didn’t plan better to give the Alliance the revamped Exodar they deserve. Velen literally helped heal the sunwell! THIS is a perfect time to revamp the Exodar and the myst isles and give the alliance their own questing zone like they did with Kul Tiras. But Nooooo we have to share and everyone is arguing with each other instead of criticizing blizzard.