Yeh Ramirez really did not have a good start, his cousin as you say was a sick fucker. A Vietnam war soldier who raped, tortured and murdered during the war and took pictures which he then showed to Ramirez at 12 years old. There was also documentation of his dad abusing him and tying him to a crucifix as punishment.
Obviously cannot condone or sympathise with his crimes but you do get an understanding that he is a product of environment, all to often abused leads to abuser