This is not eugenics though. Eugenics is when people selectively breed and kill people to improve traits. This is just a massive antisocial cult that is killing itself based of being antisocial. Their children definitely don’t deserve it either. I’d compare it to smoking in a way.
I would go so far as they don’t deserve to die for this either, but I doubt it is realistic to prescribe mental healthcare treatment to them against their will.