The difference is the perceived likelihood of malice or malicious indifference. It is fathomable that people let a dog die in the car because they don't care th

The difference is the perceived likelihood of malice or malicious indifference. It is fathomable that people let a dog die in the car because they don't care that much, or because they hate the dog. People care about their children, and if someone did kill a child like this, with malice, they'd be vilified. Heck, they might even get lynched.