Do I think that what these kids did was criminal and inexcusable? Most definitely. Do I think that the reason why they committed this heinous act should be investigated, and possibly have a bearing on the consequences of their behavior? Yes - because WHY children (or adults, for that matter) would perform such acts is important, not because it excuses it, but because it explains it, at least from the perspective of the perpetrators, and can help dictate what form the consequences should take (e.g. straight jail time, juvenile detention, commitment to a psychiatric facility, etc.) and may identify others of their peer group who may have the same impules. Also, I think it is necessary to understand why they did this, because understanding why they did it may lead to preventing others from doing the same thing in the future.
Punishment is not working as a deterrent in this country, and remediation programs are often not researched based, may be effective because of the personality of the person administering them, do not follow participants once they leave the program, as well as other issues. Education is the key to reducing crimes of all types: education about the benefits of avoiding crime in the long run, about the effects on victims of crimes, and so on, but unfortunately, such education is not a priority in the face of other issues. This type of crime is often a societal, rather than individual issue, and prevention is long-term and must be addressed at the societal level; there is no quick fix. People see crimes occur, and want to see immediate results (jail, fines, community service, etc.), but punitive programs are not working. A new, effective way to address such issues must be found, and it needs to be universal and begun at early ages... unfortunately, long-term projects requiring long-term funding are not popular with people who want to see quick fixes - which many people incarceration to be.
According to a professor in a class I took last semester, one state (at least) predicts how much jail space it will need in the future based on rates of behavior problems in 2nd grade students across the state - the money used to project and plan over this time frame could easily be used for prevention instead - but only if people will legislate for it. It is too late for these boys - they have entered the system, and the system is likely to suck them in and make them unredeemable, if they aren't already - but prevention is the long-term key to reduce, and, potentially avoid, repetition in the future.