I think they are referring to the Great Proletarian Cultural Revolution. Kids publicly denounced, criticised and some even harmed their parents but we are not sure if they killed them. This was done to achieve several things. Destroying religious practices was a part of it.
Recommended book: The cultural revolution: a people’s history, 1962-1976 - Frank Dikötter
I use the QR Scanner and several of the games. Well made.