How much of the wicked product of the enemy's "Abomination Engine™" do we need to see or know about? At one level we need the cultural memory that letting things slip has awful consequences. At a more personal level it's pointless to traumatise ourselves into oblivion so we are unable to function during reconstruction.

Each person has their own tolerance and trade-off, which is why the choice to know has to mostly be individual and voluntary. There has to be a common base (child sacrifice, genetic mutilation, paedo blackmail)... but there is only so much satanic stuff you want to expose yourself to, as it has a cost to the psyche.