You believe these things for the same reason Orwell's characters believed 2+2=5 in the novel 1984 - because that is the silly logical fallacy you have been taught all your life.
Can't say it better than that. Lest you believe 1984 is a work of fiction, it's as true today as it was in 1949, even with mass communication at the speed of light. Most of us are too busy with life to pay attention to the truth. We're uncomfortable with it. And those who try to explain the truth are likely to be censored. So the fallacy lives on and on.