It is ludicrous when you think about it. You have a neutral city such as Dalaran in which two factions reside that openly hate each other and you expect these two faction not to play tricks, spy, obstruct and sabotage the work of their enemy. That is naive. Sunreavers hate Silver Convenant, and Silver Convenant hates Sunreavers. Silver Convenant cannot understand why Sunreavers work with the Horde, they have them for traitors of their people. While Sunreavers feel the members of Silver Convenant are the real traitors. Joining hands with the same people that tried to kill their Prince, the people that drove Kael'thas in making pact with Illidan. And Sunreavers feel that members of Silver Convenant do not respect the fallen, as they still call themself High Elves, when all the rest took the name of Blood Elves, in honor of those who died during Arthas's invasion of Quel'thalas.
And that war, is the one that Vereesa Windrunner was more than happy to fight when it came to be. Vereesa just needed to be unleashed. When Jaina ordered the Purge of Dalaran, Vereesa was more than happy to oblige. Imprisoning, robbing, and killing the Blood Elves living in the city. Without remorse or regret. The most painful in this whole story is, that the one, actually, firmly and without a shadow of a doubt believing in neutrality of Dalaran and Kirin Tor was actually a leader of Sunreavers, one of the Six in the Council of Kirin Tor, Aethas Sunreaver.
What is even worse, is that this action, ordered by Jaina showed that she does not care for peace any more. Her actions were the same as those of Garithos, who imprisoned the Blood Elf forces after they defended the Dalaran against the scourge with the help of Naga. Same actions as those of Garithos who sentenced Kael'thas to death. Same actions as those of Arthas when he purged Stratholme. Yet, Garithos was a bigot, and Arthas truly believed that by sacrificing one city, he would save the rest of his kingdom. What was Jaina's excuse? Vengeance? It was an Orc who ordered the destruction of Theramore, not a Blood Elf.
Jaina's actions were lead with the intent of getting revenge. She wanted revenge for her destroyed Theramore. And because Orgrimmar and Garrosh were out of her reach, she abused power invested in her by all the members of Kirin Tor Council, even Aethas Sunreaver, and took it on the Blood Elves of Dalaran.
But that was not enough for Jaina. We see her once more on Island of Thunder, where she, leading the Kirin Tor Offensive, basically Silver Convenant merged with remaining magi of Kirin Tor. When she sees Lor'themar and Aethas she demands Aethas be given to her. She ignores Lor'themar and his demands to release the imprisoned Sunreavers who did nothing but defended the citizens of Dalaran against the attacks from members of Silver Convenant.
At the end, we see Jaina during the Siege of Orgrimmar. She once again bumps into Lor'themar. If anything it shows that at least now she can focus her hatred on Garrosh. Yet in the end cinematic, where Vol'jin is chosen as a new warchief, her words are words of panic, fear, and resentment.
Ugh... Look at them. Already they plot against us. Seize this moment, Varian. Dismantle the Horde.
Jaina is disappointed by Varian. She wanted war. She wanted blood. And she relied on Varian to accomplish at least that. She still remembers him as a gullible hot-headed fool who hates Orcs. She remembers all those times when she had to calm him down and advice peace. She remembers always intervening to keep the fragile peace in place. Yet unlike Jaina, Varian saw enough war to last a lifetime. Unlike Jaina, he has his own crumbling kingdom to run. A kingdom that is slowly falling to ruin because of ever increasing costs of war with the Horde.