Yeah, like Jeffery Dahmer, Charlie Manson, Son of Sam (in a different way) and John Wayne Gacy. Actually, most people who abused animals do go on to commit crimes against humans.
They all did that kind of thing to animals. No, it's not the same as a human, they shouldn't be punished as if they hurt a human, but at the same time, the law should definitely discourage such a thing.
Why?