Why just paedophiles? Why not physically abusive parents, too? Or emotionally abusive parents? Those do irrevocable damage to kids as well. Oh, and what about bullies? Lots of kids kill themselves because of bullying, should the bullies die, even though they're children, too? And why do we only care about the children? People commit crimes against adults, too. Should all the violent criminals with adult victims die? What about non violent criminals, like con men? (They tend to ruin far more lives than violent criminals, incidentally.)
"All the [blank]s should die" is a very slippery slope, and before you know it, you end up with a very empty world. That may or may not bother you ... I've got something of a watch the world burn desire myself, not to mention a vicious streak of my own... but you should be aware of what you're getting yourself into. The nature of life is selfish and competitive and ultimately inherently depends on hurting and killing your fellow life forms (unless you happen to a photosynthetic organism, maybe), so maybe that advice about not casting the first stone unless you're sinless yourself is wise counsel. There's someone out there that you hurt at some point in your life too, and we all tend to be a lot less keen on facing retribution ourselves than we are about doling it out to whomever the focus of our anger is.