This is also a plot point in Ursula K. Le Guin's The Lathe of Heaven. The protagonist can control reality through his dreams and in one scene, when urged by his psychiatrist to end racism, turns almost everyone on Earth into one race.
sure you can end racism, but then humans just find something else to hate about each other and the cycle continues, be it height or eye color or even the sound of ones voice.
Well to be fair, he did just say racism and only that. Which means there will still be sexism, classism, and every other -ism possible. In fact, I vaguely remember classism being an issue in early SnK.
