I understand this perspective, but Canadian law does in some instances consider circumstances that may create a reduced responsibility for behaviour. For example, women who murder their children are so unusual that the murder is typically viewed as a mental health issue and "disturbed mind" rather than criminal intent.
"The law was adopted in Canada in 1948 because juries were refusing to convict mothers of murdering their own children. Infanticide was introduced as an alternative charge with softer sentencing.
"The penalties usually aim towards supporting and assisting the mother as opposed to punishing her," Gordon said. The maximum sentence for infanticide is five years, but no conviction in Canada has resulted in a jail term longer than one year. There is no minimum sentence.
...
"It is an attempt to recognize the fact that in the post-partum period there's a great deal of disturbance in the chemistry of the mother that's given birth," he said. "As a result of that, her mind may be disturbed."
What separates infanticide from murder charges?
Boyle's actions are not a result of a bad childhood or propensity toward criminal activities, they are most likely influenced by 5 years of psychological torture. I think it has to be taken into consideration that his anti-social behaviour occurred directly after release from captivity.
I'm wondering why better supports were not in place to ensure that the family was able to better assimilate back into society. If found guilty, a psychiatric ward is where he can heal.
The alternate perspective is that he alone is responsible for his decisions and actions regardless of 5 years of torture.