Their kids often sleep alone while they party. They leave their children vulnerable to predators. These parents think hitting with sticks and straps is an acceptable way to discipline their children because that's how they were treated. Abused kids often come from homes with single parents who probably never were parented themselves. That child learns violence as a coping technique and the cycle continues.
Violence begets violence.
It's that simple. Simple enough, one would think, for even a politician to understand. If you don't break the cycle now, you pay for it in the future. And you pay dearly for it. In prison beds.