>>717820563
It's more complicated than that. Sylvanas' burning of the world tree came at the tail end of a decade+ old (crumbling) narrative of her being morally grey. Sure, the phrase had already started to become a meme already before BFA, but when the burning happened and went full evil/Garrosh 2.0 people were fucking upset (and some felt betrayed) that this was le heckin grey character that Blizzard was trying to sell and was fellating for decades.
And, at the very least, a big part of why Garrosh did what he did was of his genuine care about the Orcish Horde and his people. Sylvanas just REEEEEd over some defeated nelf's remark. She was character assassinated, plain and simple.

Also, most of nelf players were also pissed off as how they had become the punching bag of the Horde and in such a uniquely destructive way. The burning of Teldrassil surpasses even the killing of Cenarius in magnitude.