I remember when this phrase hit the news in the late 80’s, as a reason for so much of the petty crime.

I remember some people vehemently arguing that it didn’t matter what their childhoods had been like; that abuse and neglect didn’t mean a person didn’t know right from wrong.

I think, I’ve finally made a decision about my own views on the topic, 20 some years after I first became aware of the argument.

My breakthrough thought came from a conversation I had with my new primary care doc when I entered the VA system. She was getting a general health history and that included enough of a mental history to determine if I needed mental health care (I was already in the mental health side of the system but I’m glad she was checking).

She was asking about any abuse etc etc and since I was already thoroughly tired of this repetition (see “already in the … system”) I was a bit curt with my answers. I didn’t want to detail the specifics yet again to a doc that I knew wasn’t going to be involved in the care.
So after a few details, I said “you know, all the normal stuff”.
I was surprised at the force of her answer when she said “that stuff isn’t normal!”
My reply surprised even me, “it was for me”.

Now, take a kid who grew up in a bad environment. A kid who dealt with stuff I’ve only read about, every day.
If what I knew was not normal, damaging, destructive, etc etc, how could I ever expect a kid who grew up in exponentially worse situations to know what normal is?

Children learn by mimicry, they learn to survive, and whatever they live with is normal.

If a kid sees his siblings or caregivers beaten for no reason at all, or for the slightest excuse of an infraction, what is that kid going to believe is normal? What is that kid going to do when s/he’s playing with a smaller kid who then doesn’t play the game just right?

It may be true that everyone, or most everyone, is born with a basic decency (or that may just be wishful thinking), but if that basic decency decreases the chance of survival then is it any surprise that it is learned to be a detriment, a weakness, and ignored as soon as possible?

Is it really any surprise that what “society” thinks of as the innate knowledge of right and wrong is completely irrelevant to the child growing up and surviving in such terrible conditions?

Yes, I believe “they had a terrible childhood” is a valid part of a defense.

How to re-educate a child grown to adulthood in this environment, how to keep others safe from them if they cannot undo the years of survival training they’ve had so far, these are different topics.