If you look at Star Wars as myth, and then compare it to other stories, there are several instances throughout mythology of heroes slaughtering children (Herakles murdering his own children, Atreus killing and then feeding his nephews to his unknowing brother, Sigmund killing his unworthy nephews at his sister's demand, etc).

While I wouldn't go so far as to say this is a universal mythological motif, that every hero must encounter, it is present, and something the hero deals with, either to continuous downfall to oblivion, or to redemption (Herakles did it with his 12 labours, Anakin did with being a miserable cyborg for 25 years).