I guess you didn’t read A Good War. Here is some of the text. From Page 11:
Her eyebrows lowered. “With Genn Greymane in his ear? We will see.”
That was a concern, Saurfang had to concede. In the thick of the fighting against the Burning Legion, Greymane had launched a mission to kill Sylvanas. It had gotten some of Stormwind’s few remaining airships destroyed.
There were whispers that Greymane had ordered the attack without Anduin’s permission, but as far as Saurfang knew, Greymane had not been punished. The implications of that were troubling, and every possible explanation led to same conclusion: the old worgen would always drive the Alliance toward war against the Horde.
Sylvanas’s eyes glittered. “And the boy is becoming a man. What if that man decides that he has no choice but to launch a war on us?”
She pointed at the map. There was a large marking in Silithus, the place where the Dark Titan’s blade had pierced the world. “No matter what I do, that will change the balance of power. Azerite sightings are coming in from across the world, Saurfang. We still do not know its full potential, nor does the Alliance. We only know that it will create a new generation of warfare. What will war look like in twenty years? In a hundred?”
Saurfang’s voice had dropped to a low growl. “A hundred years of peace is a worthy goal.” But as soon as the words left his mouth, he wanted to take them back. He knew what Sylvanas would say.
And he would agree with it.
He thinks of Genn and his actions leading to one conclusion. The same conclusion as Sylvanas. Which he agrees with.
Yes. People will suffer under the choices of bad leadership if they allow it.
The Russians during WW 1 were tired of their leadership and overthrew it, then ended their involvement in the war.
If the civilians allow leaders to provoke war in their name, they have to deal with the consequences.
Leadership choices like Tyrande and Genn’s may be why some Night Elves, like Delaryn and Sira, are so glad to kill the Alliance - but that’s just one possible reason out of many to speculate.