If the worst form of suffering you had ever encountered was a splinter on your foot, you would make the same claims. "After reading many, many stories about the absolute horrors of splinters, I have such a difficult time understanding a belief in a benevolent god..."

The suffering in the natural world seems terrible to us, but it could be nothing in the face of larger, unknown forms of suffering. We are limited by our imaginations, having no reason to believe we have access to anything approaching deep universal truths of suffering or divinity.

I say this as an atheist. Your argument struck me as a poor one.