After losing the war against the other races, Humanity has been reduced to slavery for 30 years, 30 painful years. It is said that the humans started the conflict out of selfishness and pride. Fortunately after long years the humankind finally earned his rights back, as an equal to elves or goblins.
But minds needs time to adapt to changes, minds are easily manipulated.
And whom manipulates the mind, manipulates History.