Sometimes it is the reason in cases of serious psychosis. If you have lost all grasp on reality and you are hearing gods voice telling you to do X or Y will happen. Your brain has been essentially hijacked.
These lads have probably grown up with abuse and neglect leaving their brain easily hijacked by their amygdala. But you are right in that this is NOT an excuse. It’s a reason and part of an overall picture of why humans do shit things to each other. That helps us to predict and prevent them happening.
We all still need to be held to account for our behaviour and society still needs keeping safe.
It’s both.
If you imagine that all of your closest circle of people are killed by someone, you end up in a complete mental fug because you are grieving with no one to turn to, you can’t hold down your job, you lose your house, you turn to drugs and/or alcohol just to get through. Then you see the murderer in a dark ally. They come at you. You have a knife…
I think we are all ultimately capable of awful behaviour when we are pushed. Our frontal cortex is our braking system that helps us to control our impulses and keeps hold of our moral compass. But in extreme circumstances the best of brakes and the strongest moral compass can fail.
The brain and decision making are subject to contextual influence. And if we experience adversity early in life then those brakes (our regulation skills and our moral compass) get set a certain way. They can be more likely to fail. For these lads you can add in that their stage of development means that their frontal cortex isn’t fully developed yet, they probably have witnessed the adults around them behaving aggressively and who knows what other influences. The Jamie Bulger killers had been exposed to very graphic horror movies when little I recall.
NONE of this is an excuse. It’s just a way of understanding what goes wrong so we can learn. Consequences and risk management still need to happen. Society needs keeping safe. We are all still responsible for and should be held accountable for, our own behaviour. Justice still needs to happen.