I think this is the part that is overlooked by people. Since this story broke, the prosecutor released via email a statement that more completely described the events of the plea agreement. Apparently, the medical evidence demonstrated convincingly that their were bruises on the child's lower back and bottom. I don't know how anyone can say that bruising a child (a child who isn't even yet two) isn't abuse. Of course it's abuse.
As for the judges editorial comments - they were just that - editorial comments at sentencing. Judges, especially municipal and county judges (those that are elected) say all kinds of stupid things at sentencing. Those comments don't have any legal consequence. It's just the editorial (not legal) opinion of the bench.
When my kids abused my rules, I abused their butts, yep there were red marks on occasion...
Wife took care of minor infractions, I took care of major items...