I think this plus pg's point about "cuteness" is key - kids are ready to be emotionally mature, but parents don't want to let them have the experiences required to gain that maturity.
Exactly. The key is what pg hinted at, that parent's like their kids to be cute and innocent, which is usually self-serving if we are completely honest about it.
However, pg seems to assert that the alternative is being jaded and cynical, which does not fit with the children I know who have, for example, witnessed death up close and personal.