I think you misunderstood the point I'm making. I'm not saying every single parent who leaves a child in a car is a bad parent. I'm saying that some are, and making it a crime will deter them. I'm also saying that it can deter even good parents.
I think you're falling victim to the common fallacy where I advocate for A, you believe that A has consequence X, therefore you believe I'm advocating for X. But I believe A has consequence Y, and so I'm not in any way advocating for X.
I have great sympathy for parents who fall victim to this. But I'm more concerned with reducing the incidence of it. If treating it as a crime helps, which I believe it would, then it's well worth the tradeoff to me.
Coming at it from a personal perspective, if it ever happened to me, I can only imagine that I would be so distraught that I wouldn't care what the law did to me.