Because they are ignorant and they think there is something cool about it. What they don't realize is how ignorant they really are and that only small minded, mean, and/or stupid people would hurt an animal. Thankfully, laws are changing more all the time to better protect animals from people like that. If parents have not done their job of educating their children properly regarding animals, it will be more likely to happen. Even if someone doesn't LIKE animals there is no need to hurt them. I have never and will never stand by and do nothing if I come across someone hurting an animal. Turn them in to the police if you witness someone hurting an animal. It IS a crime.