TheX-Men's founderProfessor Charles Xavier always said that his dream was a world in which humans and mutants could peacefully co-exist, but House of X by Jonathan Hickman and Pepe Larraz proved that this was all a lie. Xavier's dream was something that set him apart from his long-time friend and rival, Magneto, who thought humans needed to be ruled by mutants. However, he never thought that humans and mutants could live peacefully together.
Xavier met Moira MacTaggert years before he created the X-Men. In House of X, Moira is revealed to be a mutant with the power to be reincarnated and retain her memories of her past lives. In each of these previous lives, Moira has tried every different way she can think of to create Xavier's dream of mutants and humans living peacefully together. Instead, she has found that everything she tries leads to the mutants' extermination. Now in her tenth life, Moira decides to show Xavier the truth of his dream before he even creates the X-Men. Xavier reads Moira's mind and sees how all of her choices to save the mutants lead to their destruction. He now believes that the only way to keep the mutants safe is to keep them separate and not have them live together with humans. Even though he says that his dream is still to have mutants and humans live together in peace, he no longer believes that.
Related: Mephisto Predicted The X-Men's Downfall on Krakoa Thirty Years Ago
Looking back on the history of the X-Men, Xavier's lie about peaceful coexistence is apparent. He has the X-Men live separated from humans in his mansion. His explanation of this is so that they can learn to use their powers. If he did believe in coexistence with humans, he would have his students attending school regularly
Read more on screenrant.com