You do realize "people like you summoned the Legion the first time" applies to Tyrande as well in this context? Azshara was as much the queen of to-be-Nightborne as she was to Tyrande. Hell, Tyrande is from Suramar. Yet something tells me she wouldn't take lightly if she was compared to Azshara.
Secondly, the Nightborne were "in deep shit" because they rose up against the Legion and sealed the second biggest Legion portal that would have turned the tide of war, making Tyrande and Malfurion's efforts meaningless, after which the Legion retaliated against them. And it's the Nightborne that were left to die. The only person that helped them was Ashamane and she sacrificed her life to buy Suramar enough time to erect the shield that saved them from the Legion's punitive army.
And whoopty doo, Ellisande made deals with the Legion. And? Collective judgment is always shitty. Especially since by the time Tyrande strolled by to spew horseshit about Thalyssra the latter already made an insurrection attempt against Ellisande for the exact same thing Tyrande (and you) projected on her, which almost cost her her life. Then, still before Tyrande and her holy indignation appeared in Suramar, launched a rebellion against Ellisande. Also over the exact same thing. And if you want to engage in collective guilt, we go back to the issue of Azshara applying to Tyrande as well.
And Nightborne haven't been the most trustworthy people? Let's look at Darnassus. Hello Druids that fucked up the maintenance of the Dream so badly Old Gods took hold in it. Hello Fandral helping the Nightmare in Stormrage book. Hello Fandral again, this time becoming a Druid of the Flame. Hello Leyara and all other Druids of the Flame. Hello Illidan, the tyrant of Outland. Hello Shen'dralar sacrificing each other to Immol'thar to maintain their power. Would you look at that, this argument also applies to Darnassus in full.
And Tyrande throwing rocks in glass houses is shit-tier diplomacy. Which bit Tyrande into her prejudiced ass. And Thalyssra joining the Horde proves nothing at this point. Because her joining the Horde was caused by Night Elves being untrustworthy in the first place. So they reaped what they sowed.
Ban'dinoriel says hi.
There is no retcon. This is Chronicle v1 lore, which predates Legion.
Do give a source for this fascinating revelation.
The Blood Elves join the Horde only at the very end of Ghostlands questline. What's more, the Warchief/Saurfang comments about the Alliance driving them to the Horde with the exact antics @Baiyn the Second was talking about.