Those people weren't making that up. Claiming their abusive backgrounds are an easy way off the hook is not it. They ACT OUT their abusive backgrounds. That's where the risk lies and that's why it is recognised. It often hasn't stopped yet.
Spot on, something.
They act them out because that is all they have ever known - it is their "normal".
And they act them out because it is a coping mechanism - in the same way that if (say_ you were involved in an awful accident, you would talk to all of your friends and family about it, and possibly a therapist, depending on what had happened, and would go over and over it in your own mind, getting a handle on it and learning to live with it and learn from it and re-establish control over the world around you which suddenly let you down in such a horrible way.
But they can't cope with it. It's too deep, it happened at too early an age when their young brains were still learning what was safe and what wasn't, and what was ok to do and what wasn't and what they learned was that nothing and no-one is safe, and that anything is ok to do if you are big enough and strong enough to impose your will on others. And that that is the only way to survive.
Many of these people have been through horrors that we can't even begin to imagine - horrors that, even if we experienced them as a confident and capable adult, would break us irreparably, and this has happened while they are young and malleable and vulnerable.
They are irretrievably broken as human beings - but it isn't their fault.
That's not to say that it's ok for them to do what they want, or to hurt and damage others - of course it isn't. Their behaviour is often hideous, and they also have children that they bring up in that image because that is all they know of parenting. They have to be taken out of society, but that doesn't mean we should kill them.