Since people aren't using science to say hereditary diseases are bad in this sense, I don't see the the relevance of the first your first paragraph
And yes, I know AB is interventionist, and it's the particular take he's explained on here that is being addressed. He argues that his god makes adjustments to DNA to bring about mankind. In order to do that it must be aware of what it is doing and understand the outcome of hereditary diseases. It therefore either chooses to create then or leaves them. AB's god is therefore a murderer that chooses suffering for children.
But the same logic also makes him the healer who chooses recovery for children otherwise you are merely and exclusively having God as the creator or allower of hereditary diseases and that is not how the universe appears to be.
So let's have a look at the charge sheet.
God has created a universe of death, disease and suffering but also recovery and healing.
God created a universe where disease at least is not inevitable where an understanding of the universes laws can lead to cures.
God has given us the will to choose or otherwise to combat diseases according to how much of a bad thing we think disease is.
Alan's God has decided that death and disease are not permanent anyway. If we are going to sling accusations at Alan's God then we should acknowledge the complete profile.