He told the court, if the offending is driven by an offender's poor and unmanaged mental health - rather than a desire by them to be deliberately cruel - then that has to be understood and properly recognised.
However the Crown contended that argument was misleading.
Lawyer Brendan Horsley told the court there was clear intent in Shailer's actions.
He says she talked about wanting to punish Moko for him hurting one of her children.
"She's not talking about some sort of dissociative state.
"She has a clear intention of causing harm from there. She bites that child."
- Newstalk ZB