How to understand that parents think locking the door is a shameful thing?

Very reasonable, because the children's housing distribution will become a shelter for children to escape communication and a hotbed for children to escape learning. From the educational point of view, children should not be given a separate room at least before the high school stage to exercise their anti-interference ability. However, if you only go to primary school, parents will never allow their children to stay in the house by themselves, mainly for fear of accidental injury and so on.