Pain & hazing rituals can be used as a way to define boundaries. Like how the surface of a steak shrivels and contracts on contact with hot oil. At the right temperature, there is no sticking. No 'unnecessary connection'.
Babies have a sense of 'newness' to them the same way new employees are 'fresh meat'. The absolute age doesn't matter as much as the relative age. They haven't been cooked to well-done by the fires of reality.