Its really simple for me: The problem is the role they have recently played in the Alliance-driven narrative.
Taking a look at BfA, they were attacked and literally burnt in their own home…but the aftermath was spent dealing with how Saurfang and the Alliance felt about it.
Not them, as they had already fullfilled their “purpose” giving us our dose of “shock value”. That’s basically the definition of the fridge trope. (*)
This isn’t the first time any of that happens.
In Cataclysm, Ashenvale questing starts with a Horde victory.
The Horde has already rolled in, curbstomped the Night Elves, burned their villages, killed their ancients, etc. And your job, as Alliance, is to salvage the situation.
A few months later we learn that the Night Elves fully reclaimed Ashenvale and set it back to rights, mostly thanks to the rest of the Alliance help.
In between, we have Wolfheart. The Horde, once again, rolls in and defeats the Night Elves. Until Varian becomes the chosen one of Goldrin and saves the day.
In conclusion, as of lately Night elves seems to perpetually have stuff happen to them to prove how bad things are, and to galvanize the Alliance (and certain human protagonists) into action.
Now, don’t you go grasping at the above and going “See?! They have it the worst!!”. They do not.
That’s the kind of “illness” that afflicts their story. Other races have their own sh!t to deal with.
But i give you that the kind of portrayal Night elves have had in the recent years, may have depended excessively on a victim card that amplifies (from a player perspective) what would otherwise be seen as a normal back and forth regarding how the race fared in the ingame setting.
(*) A character is killed off in a particularly gruesome manner and left to be found just to offend, insult, or to cause someone serious anguish. The usual victims are those who matter to the hero. If said character was killed by a villain, this guarantees to become a motivation for a Revenge plot or an immediate Roaring Rampage of Revenge.