Again, you are determined to keep everything neatly in a little box.
If we suppose (and this is partially based on Bible references I have already provided, and partially on other Bible passages which I can provide if you wish to examine them) that God created Satan before mankind, and that Satan rebelled (opposing God's will). Satan is essentially arguing that whatever he does is not wrong because God made him the way he is. Satan attempted to trap God with this paradox.
Notice that Satan challenged God as to whether God's "servant", Job, obeyed WILLINGLY or was COERCED or BRIBED.
God created mankind as an object lesson to angelic beings (among other purposes). People can choose to do evil and, through redemption, turn away from evil and choose good. This proves the existence of choice. (God did not offer redemption to fallen angels.) Every possibility and ramification of choice, both good and evil, is being played out on the human stage.
You said it is rational to think God could have prevented evil, "so long as God does not consider it evil".
But what is evil is up to Him. He has the right to command people to do whatever He wants. He calls disobedience evil. He also warns that those who continue to do evil and do not repent will receive divine judgment. Those who do repent and obey His commandments will be rewarded. And He is able to transform all the evil that has ever happened to us (who believe) into good.
These things will be accomplished when Jesus Christ returns.
Fascinating. From where did you derive this idea?
And, out of curiosity, what do you believe the "other purposes" are?
That's how logic works.
There's just one strand of our particular debate that I want to resolve. Do you consider this a rational statement: "Evil exists entirely at god's discretion although he doesn't want it to exist."
A yes or no will be best.