When parents are poor, stressful and even abusive, eventually the child will learn from the adult and be more like the parents. And since this is the only thing the child sees, the child believes its the right thing to do. Bullying is known as a behavior, it is something people learn.
Homeless people depend on any hard surface to protect them from weather, even if it is a cardboard box, for many of them it's enough. Those who have homes often take is for granted, but the homeless would give any thing for a descent roof over their heads.