Well, it’s pegged as payback for the Alliance, but not for the Night Elves. Either way, as much as Night Elf players may not give two 
's about the Zandalari, it’s still something the Alliance is proactively doing, which is probably adequate enough in Blizzard’s eyes. To be clear, I’m not saying that it’s good, only that it appears to be good enough for the devs, and they’re probably wondering why people are booing them.
There’s a pretty good post describing this in another thread: Kevin Martens and Frank Kowalkowski Interview - #8 by Jellex-wyrmrest-accord
To add, there’s no conceivable way to resolve this story well that doesn’t make the resolution seem either contrived or ham-fisted. Many will feel that their problems were not solved, because both factions have to exist after this. This is a conflict where no one will win, or lose. Wristslaps for all.