None of this casts any shade on that which I believe gives rise to God belief. I don’t imagine what we experience as God in prayer or revelation has any relation to the God that is thought to have installed everything there is in the cosmos. So I think it foolish to imagine God sitting at his watchmakers bench putting the final touches on the eyeball worm. The God we experience arises in us alone, guiding our development and holding together the world as we experience it. It is only by man’s definition that God is omni-anything. God can be all important to us in our experience without having created everything from scratch.
Edited to actually answer your question: is the the eyeball worm, childhood bone cancer or any other natural horror a knock down blow for Christianity?
My answer would be no. But that would depend on how much certainty you think you are entitled to regarding God’s attributes and intentions.