You seem to forget that Night Elf saboteurs in WOW tried to sabotage the Blood Elves magical grid while a dwarf was trying to distract them with fake diplomacy.
They weren’t that fond of the High Elves in WOW either? Remember that poor woman stuck at the end of the pier in Auberdine because the Night Elves wouldn’t let her enter town and she sends you on quests to hope they’d change her minds? Poor woman gets offed by Deathwing when he passes over.