Of course the child could have become the next Hitler. Or it could have been the next John Lennon. Most likely it would have been a bog standard, common-or-garden, lesser spotted human being, looking to make its own way in the world. How any of that warrants a death sentence escapes me. But once you've allowed your own humanity to rot away (or purport to, which in many ways is actually worse) to the point where you can say that it's better that a three-year-old child is dead than to develop its own potential, well now your own toxic existence is doing far more harm than good.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'