Its a horror in a different way. Because after this - your society is dead. The children may recover the innosence, but can you thrust any adult of your group ever again after that? Its the same effect that the survivor of mao, stalin and the likes share. You just know to much about humanity and the other to ever trust them again.

Betrayal was rife during WW2, it was a time where you couldn't trust anyone anymore. There's multiple stories about that in Maus, where people betray their own people and family to gain favors with the Nazis (there's some essays about that if you can't be bothered to read the graphic novel, e.g. here https://brandeis.digication.com/rkoehler/conflict ).

That is, the Nazis gave a Judas some food and other favors if they could find and report jews in hiding.

Specifically, from the U.S. Holocaust museum, https://encyclopedia.ushmm.org/content/en/article/jewish-cou... . I recently read the Eichmann trial coverage by Arendt, and she goes into this horrible situation in some depth. Getting people to betray and persecute each other for your benefit is probably the most essential definition of evil we have.