Pick a random man on the street, don't ask his or her 戶口, just ask if he is going to stay in Shanghai for the next 6 months, and if he has a child. If both answers are true, he's got exactly the same rights as you, and his child's got exactly the same rights as yours.His child goes to the same school with your son. You didn't do any favor to him, and he has no reason to appreciate you. He and his child are Shanghaiers the same as you and your son.
I am not saying that these rights are granted by god. But if you want to stand on the high moral ground, you have to think this way. Otherwise, you can discard and despise the pretended charity and follow the law of jungle, by doing which your will get my fully approve and support.