"I can't see the wishom behind babies dying from cancer" is argument from ignorance

[Esquilax]

It's not my problem if I can't imagine something positive coming from children with cancer that can't be achieves through other means. If someone wants to come across as a benevolent being, he has to do things that don't look like horrible ideas on the surface that need to be explained afterwards so that people understand.

This. We're only responsible, rationally speaking, for the evidence we currently have, or could possibly apprehend. If some theist wants to make the argument that something like cancer, which is objectively bad according to everything we can currently know, is actually good, then it's up to them to make that argument. We aren't obligated to follow their presupposition that there must be, or even could be, a good reason for cancer just because they insinuate the possibility.