Determinism
humans aren't responsible for their actions.
Yes! Humans are indeed, not culpable for their actions because we have no free will.
Now, I won't go into the nuances of laws here, but I do find punishing people for the sake of punishment, or out of some sense of "they deserve it" to be problematic because all humans are innocent.
Wow.
EDIT: Some of the comments on the repost on that site, 400 comments, are great.
Well, that explains it. I always wondered what Socialized Medicine was... now I know...
People used to get married all the time at 15. What ever happened to traditional values?
It seems like this site is very religious, so there is lots of moralizing, claiming that the boy had done a "mortal sign" among other things.
Because people like to make claims about human nature that simply aren't generally true. Rather than recognizing the way complex circumstances can shape human feelings and behaviors, I frequently see people break it down into simple platitudes like "humans are lazy, greedy, etc", rather than recognizing complex realities like the way power erodes empathy.
I have no such limits. Death, as a penalty, is always unjust because humans do not have free will. Every action, every thought, has some biological, or neurochemical, or material basis for it's happening. Inflicting any form of punishment or suffering on the qualia, the conscious experience of someone, for the illusion of choice we believe to have, is actually just inflicting suffering on innocent beings, because we have no choice.
Now, that's not too say I'm anti-violence. But I firmly believe that every piece of violence should be evaluated as if it was being done against an innocent person. Things like "guilt" or "they deserve it" should not be taken into the calculation when doing violence at all, only the benefits it has to the rest of society. If you are in the position to levy death as a punishment, I would rather just see them locked up for life.