I purposely worded the question in this way, to show what (I think) is wrong with the usual framing. People will often say, “Why would a good God have permitted institutional slavery, children dying from cancer, the Holocaust…etc.?” But nobody says, “Why would a good God have allowed me to stub my toe this morning?” unless the person is cracking a joke.
Now thus far it seems like I’m not contributing anything, but I’m being dead serious. If you go back and re-read the above, I think we have our answer. WHY would it be goofy for an atheist to demand, “Why would a good God let me stub my toe?” It’s because we easily recognize, “That’s a silly argument. In the grand scheme of things, stubbing your toe is no big deal, and so if a God existed we could imagine there is some reason that would trump you avoiding a toe stubbing.”
And there’s the answer.
P.S. Obviously, it doesn’t seem that way to me either. The first three things I mentioned are absolutely horrible, they’re some of the worst things of the human experience. But right–no matter how bad the absolute level of misery God permits to occur on Earth, those things (by definition) will be the worst things in history. They will horrify us. But it could be worse–remember what happens to people who cross Jabba the Hut.
C-3PO: You will therefore be taken to the Dune Sea and cast into the Pit of Carkoon, the nesting place of the all-powerful Sarlacc.
Han Solo: Doesn’t sound so bad.
C-3PO: In his belly, you will find a new definition of pain and suffering, as you are slowly digested over a thousand years.
Han Solo: On second thought, let’s pass on that, huh?
If you’re a parent, think of a typical American toddler who doesn’t get his way. He absolutely flips out; he is outraged that it’s time to leave the park (or time to turn off the DVD). That’s how we must look to people in the afterlife.