From Horde perspective Jaina and Tyrande deserve to die.
Dalaran was Alliance only under Jaina's tyrannical rule after Pandaria. Traditionally it was separate human kingdom which didn't choose to bow to Varian.The only reason the Horde has any city that isnt made of mud huts and sticks are the ones stolen from the Alliance. Dalaran was an Alliance city made neutral by Jaina. She can undo what was given, and nobody is going to tell the most power living mage "No". She already did once in the first Purge. The humans sympathetic to the Horde (wtf?) can go live in Suramar or Silvermoon.
The Alliance has lost way too many cities, and gained nothing back in years. In Legion, the Horde gained Highmountain and Suramar; the Alliance got a broken space ship and a rock drifting in the void. Reclaiming at least one city that was originally theirs to begin with are scraps at best.
Magnitude of Horde cities is obvious. Zandalar and Suramar are far more advanced thanyou called Darnassus.mud hut