From my point of view, the biggest "reason" for why God doesn't exist is because of the infinite amount of existential suffering in this world. We all know the millions who suffer seemingly unnecessarily. Yet theists act as if we are unworthy of contemplating why this suffering takes place or rather we should accept our fate. My argument is better personified by my professor -

" What theists claim is that we can't make the inference from 'I don't see any reason why God would allow this horrible suffering' to 'There is no reason why God would allow this horrible suffering'.

If I look around the room for an elephant and fail to see one, then I am entitled to conclude that there are, in fact, no elephants in the room. That's a good no-see-um inference. But if I look at the tip of a hypodermic needle and don't see any germs on it, then I am NOT entitled to conclude there there are, in fact, no germs on it. That's a bad no-see-um inference. The skeptical theist claims that looking around for reasons why God might allow suffering and not finding any is like looking for germs, not elephants."

Being the subjects of torment in the presence of an omnipotent and omni-benevolent God makes the problem of evil the elephant in the room. Not to mention all the claims of religion and God.

Here's my question:- If God exists, the question of why evil exists deserves an explanation, because it is we, as humans who are suffering. It is not the case that we don't have the cognitive capacity to understand a multi-layered co-relation, so if God exists what is the reason for evil?