If the lore crawl for Shadowlands includes the dead from Teldrassil then they’ve been utilised as some kind of soul food for The Maw.
Considering how cosmic forces works in the Warcraft universe it wouldn’t surprise me in the least if the Night Elves were made out to be a long-standing threat in the long run, and their slaughter actually prevented something worse happening like a prematurely detonated World Tree for instance.
Though it may be a simple bias the Devs had for people constantly spouting about Night Elves and their god-hood. What better way to tear them down than to have their home burnt out by savages?
I was more annoyed as Horde that we didn’t send any forces into the wreckage to investigate it. There might’ve been a hidden cache of goodies, a titan construct or some unearthed slumbering horror dwelling beneath Teldrassil this whole time.
Instead we just get shoved along to the mess that was BFAs story.