Actually, what “original sin” truly is has been debated, many believe death itself is original sin, which is why heaven is eternal.

Absolutism is a fine theoretical stance, but breaks down immediately when faced with real situations. Furthermore, someone with such an absolute stance will not make the effort to have a real debate and possibly change their stance, ergo it is not worth engaging with.

Assuming your stance is embryos are alive: the default stance of most christians is the physical act of baptism and church rites are less important than the belief, a child incapable of understanding God would go to Heaven or Purgatory. In some sects it is not the physical birth that matters but the spiritual, your spirit is what goes to Heaven, Hell, or Purgatory when the body dies, and it can be argued embryos and newborns do not have a soul per se, just the capability to harbor one.

Dostoyevsky lived before the baby hitler question. If you knew without a shadow of a doubt a child would become the a very evil person, is it more ethical to kill the child now and spare the suffering of those later, or not kill the currently innocent child but condemn the others. A child does not deserve to suffer for the same reasons an adult does not deserve to suffer. No one inherently deserves to suffer and have evil happen. However, free will can lead to suffering and oppression.

I have a few points to this.

The first being) he already has, it’s called heaven, a world without harship, strife, and evil.

The second being) the prevention of evil and the complete elimination of evil are different goals. If we are truly made in the image of god as the bible says, then god geels similar emotions to us as well. So the ultimate answer to the question of why hasn’t he is: he doesn’t want to.

The third being) who is to say he has not already, and the goal post of what is evil has moved? How could we possible know god did not create a world before this, with “true evil” only to restart it into this world.

The fourth being) in a world with free will and no evil, the definition if free will completely changes, so therefore he could, but it would not be the same to him or to us.