It’s been a few years since I watched it and none of this made sense to me. Just read the Wikipedia summary for a refresher and it’s one of the most incomprehensible summaries I’ve ever read. All I can say is that I remember taking the movie at its word more or less. Interesting idea though.
In searching for the video, (already provided in this thread) I amazingly found that this appears to be the same school where a selection of boys from the class of 2018 posed for a gleeful photo of them throwing up the nazi salute.