“Genocide” is simply not a reality in World of Warcraft. Now hear me out, you’d think it would be, but it seems that, by inference of the story we see, that genocides simply cannot happen in Azeroth.
Darkspear Trolls: When Thrall finds these guys in WC3, there’s like what, a few dozen of them left, after decades of brutalization by stronger Gurubashi, murlocks, Naga, and cutting off their own extremities to see if they grow back bigger. Presumably a fair number of them die in the kalimdor battles of the Third War. yet by the time we get to WoW? total and complete repopulation of the tribe, with ever-expanding numbers.
Tauren: When we encounter them in WC3 - and even to some extent in Vanilla WoW - they’re being nearly driven to extinction by the Centaur and their nascent Khanate. The Centaur are broken, but it’s not like the Tauren can just - OH WAIT NEVERMIND, now they have an entire city jam-packed with Tauren, and plenty to spare for cannon fodder even!
Draenei: Slaughtered by the Legion, slaughtered by the Legion’s orcish minions, with a bare handful, a HANDFUL of survivors, like tens of them making it onto the Exodar… and no doubt plenty of casualties when it smashes into a planet. Fast-forward to WotLK and poof, entire repopulation, there are Draenei everywhere, filling the Alliance’s ranks like nothing.
Blood Elves: Arthas destroys their kingdom and slaughters their population. Due to the corrupted Sunwell, a great portion of the elves begin to mutate into not-elves. Kael’Thas takes a fairly sizable contingent into the Outlands… and we kill all of them. Like really,doing a single quest in Netherstorm require s you to destroy entire cities’ worth of blood elves. But again just like the Draenei, they bounce right back and fully fill out their faction’s ranks, top to bottom like nothing happened.
Fill in with the Gilneans / Worgen. The Goblins, who are canonically survivors of a SINGLE SLAVE SHIP. The pandaren of both factions are a small subset of a splinter population of Pandaren. before Because The Story Says So™ gave Sylvanas lich king powers, even the forsaken were kind of on their last legs for a while. Which I’m sure is doubly worrying when you’re already dead once.
Throw in the allied races; how many Mag’har do you think escaped Goofy Draenor? Can there really be that many Void Elves around?
And then. AND THEN! Every single expansion is this massive galactic War of Doom, whether against Evil Space Aliens or Evil Lovecraft Gods or Evil Faction Leaders or whatever, every. single. Time. There’s this massive cataclysmic word-destroying war that the living beings of Azeroth just barely manage to scrape their way out of.
But the ranks are always refilled. Like, there’s no concern from Lor’Themar about sending his people into battle even though, by any sense of reason there’s like TEN of them still in existence after all of this. Genn greymane is perfectly happy to use his people as shock troops for the Alliance, despite the fact they are literally just a small hamlet’s worth of people. Tome after time, we see that there’s really no concern for the population sizes of any of Azeroth’s races, even by those races themselves.
This isn’t just gamey respawn things we’re talking about here. This is a story about races of beings who are on their very last legs, surviving by a thread… yet always, ALWAYS somehow managing to field sizable armies and full support lines AND a healthy civilian population, after two decades of constant apocalyptic wars. And they do so WILLINGLY, with no great worry about their future survival.
However many Night elves died in the burning of Teldrassil? Their entire population will totally recover and probably expand by another 75% in the supposed two years that fills the time between expansions in-world.
My theory: Azeroth, by canon exists in an alternate universe where “cartoon logic” is the universal law. A weird sort of grim cartoon where people CAN AND DO die… but there are always more people where that person came from, ready to step in and fill the ranks. Mass killings are a reality, but actual genocide just isn’t possible in the universe of Azeroth, as the Cartoon Logic of the universe refuses to allow it - it might mean the series woudl end!