No we should have laws and should enforce sensible penalties consistently when crimes are committed.
And also harsh punishments are not effective criminal deterrents.
When you posted: "Do you think that the Mom being prosecuted here will act as any kind of deterrent for future cases?" I saw the potential for Mr. Toad's Wild Ride, but I guessed as is usually the case with what you post that the vast potential for thoughtful discussion therein offered would pass by unnoticed.
For me the breadth and depths to which your question could lead were it to be considered carefully, implied to me at least that it was asked from a rare and complex understanding. I had hoped you would get a response from the person you asked. He's an interesting thinker, in my opinion.
Anyway, in my opinion, the whole forum could benefit from a single focus on your question. It relates profoundly, in my opinion, to a particular sickness that affects our culture and it is a real pleasure for me at least, to see what I consider to be a nuanced, dare I say enlightened, awareness driving the question.
For me, your question is not one I can answer with words as it involves a paradox that can't be resolved without a particular understanding at least in my opinion. Why would we punish bad behavior when bad behavior was created by punishment. The problem is that we do not separate the notion of punishment from guilt and revenge. Absent those emotions, punishment amounts to the least action needed to provide restraint. People cannot be free to harm others out of their own insanity.