Orwell depicts Winston Smith and Julia as ambitious individuals who live in a dystopian society. Their lives are completely controlled by Big Brother. Despite the numerous obstacles preventing Winston and Julia from being together, they manage to carry on an affair and fall deeply in love with each other. Through their romance, Winston and Julia are able to exercise their individuality and embrace their humanity. Other members of the Party are controlled by Big Brother and practice doublethink to become completely orthodox members of society. They are mundane, passive citizens who ignorantly digest the government's propaganda and loyally support Big Brother. Tragically, O'Brien betrays Winston and Julia by revealing that he works with the Thought Police. He proceeds to torture and brainwash Winston in the Ministry of Love.
A Party sympathizer would argue that O'Brien gave Winston and Julia a great gift by brainwashing them into obedient, orthodox members of society. By the end of the story, Winston and Julia are no longer in love. Both are infatuated with Big Brother, which makes their lives significantly easier in the dystopian nation of Oceania. However, one could argue that O'Brien did Winston and Julia a disservice by stripping them of their humanity and individuality, which was the essence of their beings.
O'Brien turned Winston and Julia into ignorant, mindless supporters of Big Brother by successfully eradicating the qualities, emotions, instincts, and values that made them true humans. Similarly, Big Brother betrayed Winston and Julia by eliminating their humanity, which parallels O'Brien's objective. Orwell intends to portray Big Brother and Inner Party members as authoritative, hostile beings whose primary purpose is controlling every citizen in society. At the end of the novel, Winston and Julia become victims of the totalitarian regime and tragically lose their humanity and individuality. Their conversion is meant to be viewed as the ultimate betrayal at the hands of the government.