I do think there could be something hereditary, since she is so very troubled and her sister is a recovering alcoholic or had to go to drug rehab. I do not think she was abused by her mom and pop. She would have dropped them in the grease about it, BIG TIME.
As far as her getting a spanking with a wooden spoon....when we were kids my mom carried a little paddle in her pocketbook and we would get spanked. It was not abuse. It was common for parents to spank in those days. Indeed even the school was allowed to give spankings. I recall we always had the option, do we want to take three swats from the principal's wooden paddle, or stay after school for detention. It was not abuse. It was what was done at the time. We don't do that anymore, but it doesn't make it abuse. In the words of Maya Angelou, "When we know better, we do better".
I do believe that she was born with something a bit off and then things may have been made worse along the way, but I do not think her actions can in any way be placed at the feet of her folks. Sante Kimes they were not. As far as the dad having tattoos, so what? Every uncle I have had a tattoo or two, they all seemed to have gotten them while they were in the service, as young men. These were good, upstanding, educated, church going gentlemen that perhaps would not go out and get one if they had it to do over. I recall thinking how out of place their tattoos seemed on them when I'd see them in a short sleeved shirt rather than their work suits. Nevertheless, the tattoo is no indication of a harsh person or abuser or drug gang member. The only thing I know about the dad is he is married for 35 years and has owned some restaraunts and worked hard all his life. Do I wish they could have made her get some mental health intervention, yes, of course. Do I think that once she moved out they had very little , if any.... control over her or her health decisions, yes. I also think they are unsophisticated and likely had no idea where to turn, believing that once she turned eighteen they had no legal rights to make her go get help. So they did what they knew, at the time, tried to talk to her, tried to go get her and help her move back home, etc.
This murder is on Jodi and Jodi alone, in my opinion.