Although this is quite disturbing I find people tend to overreact to stuff like this because it involves a cute animal getting killed. Not picking on anyone here but it's not uncommon to encounter people that appear to get more grossed out by violence against pets than violence against people. If these two teens broke into someone's house and killed a full grown man would this have created enough of an outrage to post here and would it attract as much attention? It would probably be considered a run of the mill crime, largely ignored outside the local area.
I would throw these kids in jail for a few years for breaking into someone's house and destroying property and some mandatory psychiatric evaluation due to them appearing to take pleasure in torturing a living creature.
I have a cat and this grosses me out a lot but I don't regard animals as equal to animals. I can't be cool with us using non-human animals as a resource (meat, leather, etc) and then regard some animals as having human rights because we keep them as pets. I see the cat as the property of the family who owned them. Thus these teens destroyed some else's property. Sounds a little cold but how can you say that a cat is deserving of more rights than a cow at a slaughterhouse? Now if these teens caught a stray cat, killed it in an efficient and humane manner, took no pleasure in torturing it and then ate it and used every bit of the animal they could would that be a problem? I'm sure a lot of people would freak out but they shouldn't. The problem is that it wasn't their cat and they killed and tortured it entirely because they found commiting the violent act pleasureable.
That part of it is the part that's really scary and that's the part that means that these kids need to be monitored. People who like causing pain for no reason are potentially dangerous to society. If they enjoy torturing a cat they may enjoy torturing a human.
The slap on the wrist they got is more of a flaw in young offenders laws. I think it's stupid that because someone is under 18 that they shouldn't be responsible for serious crimes. There are career criminals that waltz in and out of jail because they're under 18. I don't care if they don't know better. They're dangerous so get them off the street. Prision should not be seen as a punishment but rather a place to keep dangerous people away from the rest of us. A minor that kills is still dangerous, even if he's too immature to know better. Insane people don't know better either but if they're so nuts that they're a danger to everyone we lock them up. How is a crazy dangerous person any different than an immature one?