Genocides in both Rwanda and Cambodia were carried out by broad swathes of the populations. In Rwanda in particular, you had neighbor killing neighbor using mac

Genocides in both Rwanda and Cambodia were carried out by broad swathes of the populations. In Rwanda in particular, you had neighbor killing neighbor using machetes. Something similar happened in Indonesia. Likewise the Cultural Revolution in China. There wasn't much need for a Judas as there was nowhere to hide or no small group of people to hide from. Though given the scope of these events you'd expect to see every variation of human behavior many times over, so of course there are countless situations of betrayal and subterfuge, and these stories tend to resonate with people as they're highly personal and emotionally charged. People in more developed societies (or maybe just societies which emphasis individualism and individual moral agency, like many Western nations) find it difficult to fathom how such brutality could unfold at the hands of individuals without the interpersonal drama to help contextualize and connect to their own experiences.