The thing is: There is enough research on the topic, all those biased anecdotes are not needed – this all reminds me of the violence discussion (I was beaten, it didn’t harm me). You can quite accurately tell who has been in daycare within the first 18 months based on the cortisol levels of teenagers. These stress levels persist throughout childhood. Children in longer and more extensive daycare (and I don’t mean grandma or anything like that, but a daycare center) under one year old are almost always worse off than comparison groups. From one year on, excellent care quality can at least ensure that the child does not develop worse than comparison groups. Only from 18–24 months does this balance out, but even then it highly depends on the quality of care and the child. Only after that do communicative developmental aspects promoted by daycare and such really come into effect.
But we are in Germany, and Haarer’s spirit still wanders through many children’s rooms here...
"The best place for the child is in its own room, where it then remains alone," Johanna Haarer also wrote in her 1934 guide The German Mother and Her First Child. If the child starts to cry or scream, one should ignore it: "Just don’t start taking the child out of bed, carrying it, rocking it, pushing it in a stroller, or holding it on your lap, not to mention nursing it. The child understands incredibly quickly that it only needs to scream to summon a sympathetic soul and become the object of such care. After a short time, it demands this attention as a right, giving no rest until it is carried, rocked, or pushed again – and the little but relentless household tyrant is complete!"
It is and remains creepy.