Think about it this way. Most people have thought to themselves "I'd love to kill that son of a bitch." Even if they don't entirely mean it (because otherwise, they would have done it). No one other than a pedophile has even thought about bending over little Timmy.
Murder is more... normal.
That's a good point, and I do understand it on that level. It's just one of those dichotomies where reason (which should be source of court judgment in the end) strongly deviates from gut reaction.
EDIT: Another factor in it is also that we, as a society, have the responsibility to care for our children, whereas we don't for the general public so much. So, when a child gets harmed it is a direct affront to something in our care, whereas a random murder affects a person we, by default, don't even care about.
rumborak