So they don't thank the Alliance at all for their help nor do they wish to join them all because Tyrande was cautious with them? Completely disregarding the fact that they might be able to have great bonds with other races in the Alliance, they decide to join the Horde which is full of goblins, undead, orcs and trolls. The latter hate elves.
And that's somehow a BETTER choice than Tyrande's cautionary approach to them? It's so, so ridiculous. Dignity? Yeah good look having dignity in the Horde, Azeroth's rejects.
The Nightborne then call the Alliance stagnant. STAGNANT? What's stagnant about it? Sounds to me like Tyrande is completely right in being wary of the Nightborne, who seem to imply they want to seek power at any cost once more. And they call TYRANDE too proud! Holy smokes, the irony going on here!