While I have no doubts he was harsh in war, I have never heard the claim the claim that he ordered the rape of children until recently. I have my doubts about this, but was ordering is there any evidence that points to this being true?
Where did you see that? The Mfecane (The Crushing) was certainly a war crime by modern definitions, and I'm sure infanticide and the threat of infanticide was part of that policy, but I cannot recall reading about mass child rape as a tactic of Shaka kaSenzangakhona. I feel that is the sort of thing I would remember.