No human being was harmed, it is true, but hedgehogs are not pizzas, they are living and, more importantly, sentient creatures. It was an act of appalling cruelty reflecting a singular lack of compassion for living things. Many people do find this disgusting.
Mr Emerson wrongly asserts that the law has a higher obligation than to reflect society's disgust. It is not a crime to lack compassion, it is to give expression to it, and the law against cruelty to animals is on the statute books for the same reason other criminal law exists, because society finds the actions proscribed to be seriously unacceptable.