And even if the guy had a serious brain malfunction impelling him to kill at the first sight of flung popcorn, he is still guilty of manslaughter. He still was packing when he shouldn't have been. He still, by your own post, expressed horror at his own choices after he killed a man. And he deserves to be punished for not having developed self-control, especially after having sworn to "protect and serve" all those years. Face it. Even if he had run over a man with a car "by accident" because he's old, he would face jail time. And would deserve it.
Sorry to mislead you, the book does not refute thousands of years of human experience. What it does do is focus on the break through that scientists made due to the unusual condition of one man who lost the ability to transfer short term memory to long term memory due to an illness.
What came out of that was new insight into habits and how they are not governed by the part of the brain we attribute with thinking. Instead habits are lodged in the primitive brain.
And that’s the point, habits are not subject to as much self control as most believe. Folks with bad habits are considered to have poor self control which is now known not to be the case.
You can never get rid of a habit. You can develop a new habit instead. But the old habit remains and can resurface in times of stress. The book was a constant stream of Eureka moments for me. It provided the answer to issues with human nature that I’ve been wondering about for most of my life.
For some situations it explains why smart people do stupid things.