Heck, they bent Warcraft lore into a pretzel right from the start with WoW. They annihilated the story they were wanting to tell because they needed two factions.

End of Warcraft III: Orcs, Night Elves, and some of the Humans are all allied against an imminent demon invasion.

Frozen Throne: Humans from Stormwind go full racist and kick out the regular Elves.

Beginning of WoW: Orcs and Humans are suddenly at war. More inexplicably, the Night Elves and the Orcs are at war, and the Night Elves are buddy-buddy with the racist Humans that just got finished kicking out the regular Elves. The Orcs which just got finished fighting waves of Undead are now allied with the Forsaken, because reasons.

Burning Crusade: The Blood Elves, who fought with Illidan against the Undead, suddenly decide to join up with the Forsaken, also known as the Undead that destroyed their homeland and a significant portion of whom are actually the twisted mockeries of their own people. And the Forsaken still haven't stopped being full-bore evil during all this time. Oh, and the Draenei suddenly have starships, and their old lore (including what they look like) is completely ignored. What.
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Seriously, it's like they cherry picked a few plot events from Warcraft III and then made everything else up on the spot. By the time Illidan was the Big Bad Evil Guy of Burning Crusade I was just shaking my head and laughing. That's when I stopped caring about the lore at all, because Blizzard obviously didn't give a damn.