Most Christians accept that God has given us free will to go with our conscience. We are to form our conscience and then make acts of our will in conformity with God's Will. Of course we have a tendency towards sin, even after the Sacrament of Baptism; that scar of original sin called concupiscence.
So we sin.
The mess that people make of their lives often have truly mitigating circumstances. But I truly do not believe that mitigation is an excuse.
There has been a recent case in the news of a man who killed a number of prostitutes. He is now threatening suicide from prison. His girlfriend seems to think she is partially to blame somehow and his family are all rushing to the cruddy MSM with stories of how this poor benighted man was abused as a child and that's why he became a murderer, in a kind of, he couldn't help it, it was inevitable kind of way.
How can someone repent when everyone says, it wasn't your fault- you're a victim?
How can people who are abused rise above what has happened to them when encouraged only to see themselves as a victim?
My older children were hurt by a young man some years ago. He was set on doing serious damage to one of them in a way that still makes me feel sick. Fortunately I found out before it was too late.
I forgive him. He isn't sorry of course, but I see he is the way he is because his father is detached and doesn't 'father' his children and the mother has enabled and colluded with her son's behaviour rather than trying to stop it. It's her behaviour I find hard to forgive because she chose to let her children behave like that and by not dealing with it; by actually enabling the bad behaviour, she allowed her children, and particularly her son to put other children at serious risk.
We are all wounded, broken people in some way. But we are all called to properly fulfil whatever task God calls us too.
I swore an oath when I was young that I would never do to any children I had, what was being done to me. I kept my promise. I am not a perfect parent and I doubt we would make it into the Dr Ray book of excellent parents; but I really don't think a bad childhood is going to stand as an excuse on the Last Day, I really don't.