the school system is the larger part of this. you could read this as a kind of dream version of the literal truth of school in which you are snatched away from home, tortured, experimented on and sorted into various streams which then determine your life outcomes.
I remember seeing as a child the bit in planet of the apes where charlton Heston finds his friend in the cafe captured by apes and his friend is just... not there. His mind has been zapped. He doesn't recognise him, he can't talk. He's alive but he's been erased. Very horrifying, very disturbing for me to see that. A terrible fate.