Children, at least all the ones I know, are tiny little savages.
If you’ve never read Lord Of The Flies, you should. The story indicates quite clearly why children are not allowed any real power.
It’s not insulting in this case to call children tiny savages. It is, rather, a statement of fact.
Basic empathy is only partially automatic. The behavior associated with empathy is learned, to be more specific. Children have limited life experience in most cases. They may feel empathy, but not understand it. Without a clear understanding of that emotional connection, they cannot be expected to behave appropriately.
Thus, children are little savages. Very little ability to act appropriately on feelings of empathy or sympathy, and almost no life experience to boot.