Let me give you a real life ongoing case that I'm involved with. A kid is taken from his mother at birth for neglect. He's in the system until he's 18 months and during that time was transferred to several foster homes. Those early months are the most important bonding month's in a child's life. He goes back to his biological mother, who had been raped by her cousin, which resulted in his birth. So he's a product of incest. For the next 6 years he's raised by his mother, who is mentally ill herself, and on welfare. He's raised in apartments with no furniture,he's taught racism, to abuse people to get his way, etc. At the age of 7 a baby brother is born. Both he and the baby go back into the system. Baby goes to foster care and is eventually adopted, he goes to several different group homes before he settles at one. Mom's parental rights are terminated. The 7 old, now 9, finds out that his biological father has been murdered. He never had a relationship with his father, but any hope of a relationship with him in the future is now gone. So at the age of 9 he's an orphan in the custody of the state. He's lost everything. His mom, his brother, his father, his extended family, everything. He's angry, violent, diagnosed with attachment disorder, which in mental health is the worst. It results in an inability to form normal loving relationships with others. He is now 11. He can't stay in school because of his anger and aggression towards other kids. He gets pushed to the 4th grade after 3 years in the 3rd grade, not because he was ready to move on, but because you can't have an 11 year old in the classroom with a bunch of 8 year olds, it's not safe. He goes awol occasionally from his group home and has been arrested multiple times for larceny, arson, vandalism, etc and has been charged with two felonies. This kid will most likely never get into a foster home, never be adopted, and age out of the system full of anger and with the attachment disorder. When you have that disorder you don't care about people. You don't care who you hurt or how you hurt them.
As for Lawrence Phillips, he experienced many traumatic events.
Phillips’ anger stemmed from childhood trauma, including being abandoned by his father as an infant and being kicked out of the house by his mother at age 12 and left to wander the streets for a year.
This is probably only a small portion of what he experienced.
Each time a child experiences neglect, abuse, is moved from a caregiver to a new caregiver, etc it's a traumatic event. The trauma builds and builds. These kids don't trust people, they don't care about people. They're in survival mode on a day to day basis. They have been hurt and betrayed by people their whole life. Hurt people, hurt people.