Its what makes the Amani/Elf conversation and situation so compelling. They were exiles (rightfully or not given their insistence on magic given what ‘recently’ happened) who were going mad in Lordearon and dying, choosing just took a shot at going east and eventually north. (Should note here they contemplated about wiping out the humans to settle in some of their areas but chose not to. Somehow same logic didnt work the same with trolls 
)
Still, exiles dying and going mad in need of a place to settle intentionally settle on major leyline convergence and start to heal. Trolls angry that the same Highbrone that destroyed the world, and their empires previously, are now settling in their lands, sacred lands at that, and try to fight them back. Elves take lands that rightfully belong to them and for the next X years attempt to reclaim what is theirs.
There are varying degrees of correctness and wrongness here by modern Azeroth. We can say the Amani were ruthless and uncaring for exiles, we can also say elves did have other options We can say the elves likely didn’t care of the trolls who they saw as beneath them, we can also say the trolls harbored hate from generations prior. We can say they should have attempted some agreement over the generations, but who is to say any would have been satisfying to all parties? This is one of the actually morally grey things the game offers.
WoW Player Challenge: Understand game narratives and our understandings don’t happen in a vacuum.
Difficulty: Impossible