How did Lilliputians ensure an abuse - free childhood for their children ?

The children would not get abused by their parents because the children in Liliput aren't raised by their parents; they are raised by the kingdom. Not only are their parents not responsible for raising their children, but they don't live with their children either. They do get a great education however, although their writing is a bit strange.

Children are sent away to live at school when they're very, very young. Kids go to schools that are chosen in accordance with their parent's station and finances. Children of farmers stay home to work.

The difference between the children in Lilliput and modern society is that although many children continue to attend boarding school, their parents still have responsibility for raising them, and it is a decision of choice rather than being forced to attend one specific place.

We are not placed in school according to our financial or societal stations, and we are not limited to seeing our parents only twice a year. No child is exempt from attending school (unless they're being home schooled), and the children of farmers help their parents after school or during the summer.