Roger Olson doesn't like the idea that God ordained the fall. He claims this makes God the "author of evil." I'll go into further detail on this in my review of his book Arminian Theology: Myths and Realities. For now I'll focus on his answer. One of Olson's rejoinders to Calvinist answers is that our idea of God is one "whose goodness bears no real analogy to the best of human goodness" (111) and his justice "cannot be so foreign to the very best [human] understandings of justice ... that it is emptied of meaning" (120). This is a problem because, apparently, the most moral human would never "ordain," say, the holocaust. Or an axe murder. Or a rape. You get the point.
According to Olsen, God doesn't ordain sins, but "every human act, including sin, is impossible without God's cooperation" (121). God is not a "spectator" (121). "God ... cooperates with the creature in sinning" (122). Of course God can cooperate in a sin "without being tainted" (122). Apparently he can do this but can't ordain sin "without being tainted." More on this in my review. God cooperates but he does so "reluctantly" (123). He even does so "unwillingly" (123). He has the power to stop sin, but permits it anyway. He gives all sinners the power to commit sins that they would be unable to without his giving them the power. He does so because free will is so important to him that it's worth cooperating with the sinner so he can commit the sin (see 121-124).
Okay, let's now hold Olson to the standard he holds the Calvinist to. Would a "highly moral" human "permit," say, the the holocaust, or an axe murder, or a rape - you get the point, if he had the power to stop it? What would a "highly moral" human say about someone who did permit one of those things to happen when he could have stopped it? Would a "highly moral" human cooperate with a criminal to commit a criminal act? Apparently it is justified because libertarian free will is such a high good that the ends justify the means. For me, I don't share this intuition, indeed, it seems downright false. But let's not focus on that. Let's extend our thought experiment.
Say a "highly moral" human, Sally, invents a pill that can make the lame walk. Now, imagine a quadriplegic man. Call him Harry. When Harry meets Sally he lets her know that he would very much like the power to walk. Harry isn't the sharpest tool in the shed and so he lets Sally know that his desire is to kill his neighbor's 10 year old - that snot nosed, annoying punk who always called Harry the most awful names and said, "Nee ner nee ner, you can't get me." He wants to torture him for a while, cut off his legs, taunt him to "come and try and get him," and then pour gasoline on him and burn him alive. Would Sally, our "highly moral" human, give Harry the power to kill the 10 year old so that Harry could exercise his free will to the fullest? How about if there was a good that would come out of it? Say that Harry would come up with the cure for cancer while sitting in jail (purely by accident, of course, since he's not so sharp)?
If the answer is no, then Olson denies the very rules he makes us play by. If the answer is yes, then the "goodness" of a "highly moral" human is stretched such that Olson's argument ceases to be a relevant rebuttal to the Calvinist theodicies. Therefore, either Olson plays with a stacked deck, or his argument has no force against the Calvinist.
None of this is to deny the greater good theodicy. It simply defeats the defeater that the Arminian uses to defeat the Calvinist's answer. It simply shows that we can't claim God is immoral for doing p just because a lot of humans think p is evil.1 The problem here is the different agents. Humans are finite and we can appropriately judge most of their actions and reasons. God is infinite and so his his plan. The rebuttal here is one offered by many Arminian philosophers. It's called the skeptical theist response. The Arminian just isn't going to win the problem of evil argument against the Calvinist. I suggest they give it up. This entails that I am suggesting they give up their number one argument against Calvinism. What's more important? Intellectual integrity or defeating the Calvinists by self-excepting yourself from the very critique you give them? The latter isn't intellectually virtuous. Does Arminianism require its adherents to hold to intellectual vices? Or is this another "myth?" We'll wait and see.
1 To be clear, I deny virtually all of the intuition based Arminian moral arguments, what they lay at God's feet doesn't strike me as immoral, I'm granting some stuff for arguments sake. I'm answering Olson &c. on their own terms.