It's crazy to me because it's not particularly hard to set up history and hatred between races. Having a basic knowledge of human history would help but since these turds like video games, there's plenty of good examples of racism in them.
Like, take Dragon Age Origins for instance. Why is there so much animosity between Humans and Elves?
At first when humans arrived on the scenes, Elves thought them inferior because they barely lived to be a 100 years, were warlike and brutish as all hell. Our arrival brought our diseases to them and for whatever reason, being around humans made Elves actually age, meaning their immortality was worthless. Strike 1 why Elves don't like humans.
Then the tevinter imperium rose to power and completely fucking destroyed the Elven homeland. Some elves fled, many were enslaved. The runaway elves tried to rebuild their homeland elsewhere but it was destroyed generations later by a Holy Human Crusade. Two more strikes as to why elves hate humans. These conquests also basically obliterated Elven culture entirely, with some outsider elves still trying to hold onto what little they have left but most elves basically opt to just live among humans now instead.
City Elves (Those Elves that live among humans now) live in impoverished ghettos within human cities and work as house servants for rich humans in the quarter. We have multiple slurs for them and they're used in game. (Knife Ears, Slant Ears, Rabbit) You can see how little humans care for Elves more if you play the City Elf Origin story, wherein your arranged marriage ceremony is interrupted by several human nobles who kidnap a bunch of women (You included if you're a female) and basically plan to rape them. Even killing one that tries to resist right in front of you.
Setup, retards. It's not hard.