Firstly, I agree with the idea that a dystopian society is not necessarily an evil place, but a lost one, controlled by bad people. Based on movies and novels, I would define dystopia as based on the state society is in at the time of the novel. Generally, it is everyone acting uniform, living by strict rules put into place by a higher order and forced to follow them through intimidation or fear of something terrible happening to them. It is an act of blind patriotism and following of an imaginary figure such as big brother or a higher society. Cameras everywhere, no sense of individuality, no control over yourself or your interpretation of life, just sadness, uniformity, and being trapped in an inhumane society.
For example, you have novels like 1984, Fahrenheit 451, or even The Hunger Games where people constantly live in a state of fear and poverty, fighting for food, surviving off of rations, stuck in the same clothes given to them by the government, even as far as having an upper-class society that makes rules and are allowed to break them simply because of their status. There are burning of books, limited-to-no movies, brainwashing in schools and so much more that turns them into brainwashed patriotic members of society with no real perspective, personality or sense of self who constantly live in fear of disappearing if they rebel against big brother or the upper class. It’s a common theme in all, so do I believe there is one sentence that can define dystopia as a whole? Absolutely not, because dystopia is implied by the state of society rather than defined by a singular thing.