In Confucianism, the relationship between a father and a son, a superior and their subordinate, a state and its citizen are considered equal. Therefore it is considered normal for the state to be paternalistic. Also, collective responsibility takes precedence over individual freedom. Each person is supposed to conform to its role in society. Children’s role is to study, rather than play video games all night.
Together, you get a video game ban, enforced by the full power of the state.
Until a few years ago, video game consoles are banned in China for the exact same reason.