The nightborne represent the height of the kaldorei empire that humiliated the Zandalari - you can imagine that SPellblade Aluriel was leading some of those fights with Night warriors and Moonguard in toe... and while I'm sure they hate night elves, I can't imagine they love nightborne at all.
The nightborne aren't subsequent generations who cannot be blamed for the actions of distant ancesotrs, they are the very same night elves, just like the Darnassians are who were around 10k years ago, some of them wiping out trolls too. Only difference is they look a little different.
While there is a horde, and the nightborne are part of it, gosh i'd love tos ee some racial tensions. I do not imagine blood elves love darkspears and only put up with them because they have to, for the sake of the horde.
However, my view point may be outdated, is there any lore that has come laong to forge friendships between elves and trolls? I mean anything specific that is not a one off but indicative of a wider change in perception?